Your marketing can’t bring customers back if your messages never reach them.
Auto repair shops rely on email and text messaging to remind customers about recommended services, recover declined work, promote seasonal offers, and encourage repeat visits. But sending a message doesn’t guarantee that a customer will receive it.
Email providers and mobile carriers have systems designed to protect people from spam, fraud, and unwanted communication. If your shop suddenly begins sending hundreds or thousands of marketing messages from a new email domain or phone number, those systems may treat the activity as suspicious.
The result? Emails can end up in spam folders, and text messages can be filtered or blocked before customers ever see them.
Even worse, poor marketing practices can potentially affect the everyday communications your shop depends on, including customer estimates, appointment updates, and service notifications.
That’s where email and SMS warming come in.
Warming helps establish a positive sending reputation so your shop can communicate with customers more reliably. Understanding how it works is especially important when implementing a new auto repair CRM, switching marketing platforms, or launching automated marketing campaigns.
What Is Email and SMS Warming?
Warming is the process of establishing a trustworthy sending history before increasing marketing activity.
For email, this typically means starting with a smaller group of engaged customers and gradually increasing the number of messages sent as providers see consistent, legitimate activity.
For SMS, the process is different. Mobile carriers place significant importance on business registration, customer consent, message content, and approved sending limits. Gradually introducing marketing traffic can help identify potential problems, but it does not replace registration and compliance requirements.
The goal is the same for both channels: Build trust, maintain consistent sending practices, and avoid behaviors that could cause messages to be blocked or filtered.
Warming isn’t about tricking spam filters. It’s about demonstrating that your business sends legitimate messages customers want to receive.
Why Warming Matters for Auto Repair Shops
When a shop implements a new CRM, one of the first priorities may be launching a customer reactivation campaign. The temptation is to immediately send a promotional email and text message to everyone in the customer database. However, sending a large volume of messages without properly preparing the email domain and marketing phone number can create several potential problems.
The shop’s email domain may have little or no established marketing reputation. Its phone number may not be properly registered for application-generated text messaging. Some customers may have outdated contact information, while others may not have agreed to receive promotional messages.
Sending a large campaign under these conditions increases the risk of bounced emails, spam complaints, unsubscribes, and carrier filtering.
These problems can also affect future campaigns. In some cases, they may interfere with the operational messages customers rely on.
A better approach is to prepare the sending infrastructure, verify customer permissions, and introduce marketing activity in a controlled way.
This helps protect deliverability while giving the shop an opportunity to identify and correct problems before they become widespread.
How Email Domain Warming Works
Email providers such as Gmail, Yahoo, and Microsoft evaluate incoming messages to determine whether they should be delivered to an inbox, filtered into spam, or rejected.
They consider factors such as sender authentication, sending history, recipient complaints, and engagement.
A new marketing domain or sending infrastructure may not have enough history for these providers to establish a strong reputation.
Email warming helps build that history.
Step 1: Authenticate Your Email Domain
Before sending marketing emails, your domain needs to be properly configured.
Three important email authentication technologies are:
- SPF (Sender Policy Framework): Identifies which mail servers are authorized to send email for your domain.
- DKIM (DomainKeys Identified Mail): Uses a digital signature to help receiving providers verify that messages are authentic.
- DMARC (Domain-based Message Authentication, Reporting, and Conformance): Helps protect your domain from unauthorized use and tells receiving providers how to handle messages that fail authentication.
Your CRM or email marketing provider should help configure these records.
Proper authentication is essential, but it doesn’t guarantee inbox placement. Your sending behavior and customer engagement still matter.
Step 2: Start With Your Most Engaged Customers
Not every customer in your database should receive the first marketing campaign.
Start with customers who have agreed to receive marketing and have recently interacted with your business or its emails.
For example, a shop could begin with customers who recently visited for service and have demonstrated email engagement. Once the sending reputation is established, the shop can gradually expand to other eligible customers.
This is where advanced customer segmentation becomes valuable. Instead of sending the same message to every customer, a CRM can help identify which customers are most appropriate for each campaign based on their service history, communication preferences, and engagement.
The objective is to begin with relevant communication that customers are likely to appreciate.
Step 3: Gradually Increase Email Volume
Rather than sending thousands of emails immediately, gradually increase volume while monitoring performance.
For example, a shop with a new marketing domain might begin with 50–100 emails per day, increase to a few hundred as results remain healthy, and eventually work toward its normal campaign volume.
There is no universal warming schedule. The appropriate pace depends on the domain’s sending history, email provider, audience quality, and delivery results.
An established domain with a strong reputation may need less warming than a brand-new domain.
The key is to increase volume based on performance, not simply because another day has passed.
Step 4: Monitor Email Deliverability
Sending more messages isn’t necessarily a sign of progress.
Your shop should monitor whether emails are being accepted, delivered, rejected, or marked as spam.
Important indicators include:
- Bounce rate: How often email addresses are invalid or messages cannot be delivered.
- Spam complaint rate: How frequently recipients report messages as spam.
- Unsubscribe rate: Whether recipients are choosing to stop receiving your marketing.
- Delivery deferrals: Whether receiving providers are temporarily delaying messages.
- Customer engagement: Whether recipients are clicking links, replying, or otherwise interacting with your emails.
Google recommends keeping spam complaint rates below 0.1% and preventing them from reaching 0.3% or higher.
If negative signals increase, your shop should slow down or pause sending until the underlying issue is resolved.
Why Your Shop Should Use a Dedicated Marketing Email Subdomain
Your shop’s email domain is an important part of your business identity. It’s how customers, vendors, employees, and business partners communicate with you every day.
Using that same domain for large-scale marketing campaigns can introduce unnecessary risks.
A shop using yourshop.com for everyday business email relies on that domain to send estimates, communicate with vendors, respond to customers, and handle other important business matters through addresses such as service@yourshop.com.
When the same domain is also used to send thousands of promotional emails, the shop introduces additional risk. If those campaigns generate high bounce rates, spam complaints, or other negative signals, email providers may begin treating messages associated with the domain more cautiously, potentially affecting the delivery of important business communications.
The potential problem goes beyond marketing. Your everyday business emails could also be affected.
Important messages, including customer estimates, invoices, and vendor communications, may be more likely to encounter filtering or delivery problems.
How a Marketing Subdomain Helps
A better approach is to use a dedicated marketing subdomain.
For example:
| Email Purpose | Example |
|---|---|
| Everyday business email | service@yourshop.com |
| Marketing email | offers@updates.yourshop.com |
A marketing subdomain allows your shop to establish a separate sending identity for promotional campaigns while maintaining its primary domain for normal business communications.
This separation offers several advantages:
- Reduces reputation exposure: Marketing activity is less directly tied to the primary domain’s sending reputation.
- Improves monitoring: Makes it easier to evaluate marketing email performance separately from everyday business email.
- Simplifies troubleshooting: Helps identify whether deliverability problems originate from marketing campaigns or operational communications.
- Supports future growth: Provides a dedicated sending identity as your marketing volume increases.
However, a marketing subdomain is not a complete firewall. Email providers can associate subdomains with their parent domain, and poor sending practices can still affect the broader domain’s reputation.
A dedicated subdomain reduces risk, but it doesn’t eliminate the need for proper authentication, permission-based marketing, and responsible sending practices.
Protect the Email Your Shop Depends On
A promotional campaign that lands in spam is a missed marketing opportunity.
An important customer estimate or vendor email that never arrives can create a much bigger operational problem.
Separating marketing email from everyday business communication is a relatively simple precaution that helps protect both.
For shops implementing a new CRM or email marketing platform, establishing a dedicated marketing subdomain should be part of the initial setup process, before the first campaign is sent.
How SMS Phone Number Warming Works
Text message marketing has a different set of requirements.
Unlike email, where gradual volume increases are a common warming practice, SMS deliverability depends heavily on business verification, messaging registration, customer consent, and carrier rules.
A newly registered phone number does not necessarily need weeks of warming before it can send messages. However, monitoring initial traffic and avoiding sudden, unexplained changes in sending behavior are still sensible practices.
Step 1: Register Your Business and Messaging Campaigns
In the United States, businesses using standard 10-digit phone numbers to send application-generated text messages generally need to register through the A2P 10DLC system.
A2P stands for Application-to-Person, while 10DLC refers to 10-digit long code phone numbers.
Registration identifies the business sending the messages and the types of communication it intends to send.
The process generally includes business verification, campaign registration, documentation of customer opt-in procedures, and compliance with messaging requirements.
Registration also helps determine the sending limits available to the business.
A registered number is not automatically guaranteed delivery, but an unregistered or improperly registered number can experience significant filtering or restrictions.
Step 2: Verify Customer Consent
One of the most important requirements for SMS marketing is customer permission.
Just because a customer provided a phone number when scheduling an appointment does not mean they agreed to receive promotional text messages.
Appointment reminders, service updates, and marketing offers can have different consent requirements.
For example, a customer might agree to receive appointment confirmations but not promotional offers about tires or maintenance services.
A centralized customer communication hub can help shops maintain accurate consent records, manage customer conversations, and honor opt-out requests across their communication channels.
Consent is not only a compliance issue. Sending unwanted messages can damage your reputation and reduce customer trust.
Step 3: Introduce Marketing Messages Gradually
Once your business and messaging campaigns are properly registered, you can begin sending messages within the applicable limits.
For a new number, a conservative approach is to begin with a smaller group of customers who have explicitly agreed to receive marketing messages.
Monitor delivery results, carrier filtering errors, opt-outs, and customer responses before expanding campaigns.
Unlike email, there is no universal carrier-defined SMS warming schedule. Some properly registered numbers can support substantial sending volumes immediately, depending on their approved limits.
The goal isn’t to artificially generate traffic. It’s to establish reliable messaging practices and identify problems early.
Step 4: Monitor SMS Deliverability
Your CRM or messaging provider should make it possible to identify potential delivery problems.
Pay attention to failed messages, carrier filtering errors, STOP requests, and changes in response rates.
A sudden increase in failed messages may indicate a registration problem, an issue with message content, or carrier restrictions.
It’s also important to recognize that a message accepted by your messaging provider isn’t necessarily delivered to the customer’s phone.
Monitoring delivery receipts and provider error codes provides a more accurate picture of SMS performance.
Should Your Shop Use Its Main Phone Number for Marketing Text Messages?
Your shop’s primary phone number is one of its most valuable customer communication assets.
It’s the number customers call to schedule appointments, ask about repairs, approve estimates, and get updates about their vehicles. It’s also the number listed on your website, Google Business Profile, and other business directories.
Using that same number for high-volume promotional text messaging may create unnecessary operational risks.
What Happens If Your Main Number Gets Flagged?
Mobile carriers use filtering systems to identify unwanted or suspicious text messages.
If your shop sends marketing messages without proper registration, customer consent, or appropriate sending practices, carriers may begin filtering or blocking messages associated with the number.
The immediate consequence is that promotional messages may fail to reach customers.
But if your shop also uses that number for important operational texts, those communications could be affected as well.
Customers rely on text messages for important updates, such as knowing when their vehicle is ready for pickup, while service advisors use them to request approval for additional repairs. If those messages are filtered or blocked, communication breaks down, potentially causing service delays, customer frustration, and lost revenue.
A marketing deliverability problem can become a customer service problem.
Importantly, SMS filtering does not automatically mean carriers will block ordinary voice calls to the same number. Voice and messaging services have different systems and controls. The primary concern is protecting the reliability of your shop’s text communications.
The Benefits of a Dedicated Marketing Text Number
One way to reduce this risk is to use a separate phone number for promotional SMS campaigns.
For example:
| Communication Purpose | Phone Number |
|---|---|
| Main shop phone and service communication | (801) 555-0100 |
| Promotional text messaging | (801) 555-0140 |
This creates separation between the number customers depend on for service and the number used for marketing campaigns.
A dedicated marketing number provides several advantages:
- Protects operational communication: Reduces the chance that filtering associated with promotional messaging will affect service-related texts sent from another number.
- Separates messaging activity: Makes it easier to monitor promotional campaigns independently from everyday customer conversations.
- Improves troubleshooting: Helps identify whether problems are specific to marketing traffic.
- Supports different communication purposes: Allows the shop to manage marketing permissions, opt-outs, and messaging workflows separately.
However, using a separate number doesn’t eliminate compliance requirements. Both marketing and operational messaging must follow applicable registration and consent rules.
A separate number also doesn’t guarantee that carriers will treat all traffic independently, especially when numbers share the same business registration or messaging infrastructure.
There’s Also a Customer Experience Tradeoff
Using a separate marketing number introduces another consideration: customers may not recognize it.
A customer who has always communicated with your shop through its main phone number may be confused when a promotional text arrives from an unfamiliar number.
That’s why marketing messages should clearly identify your business.
For example:
“Summit Ridge Auto Care: Your vehicle may be due for its next maintenance service. Schedule an appointment today and let our team help keep you on the road. Reply STOP to opt out.”
Using a consistent marketing number, recognizable business name, and clear opt-out instructions helps customers understand who is contacting them.
The number should also support replies and provide a way for customers to connect with your shop.
Is a Dedicated Marketing Number Always Necessary?
Not necessarily.
Many shops successfully use their primary business number for both service communications and marketing texts, particularly when their messaging provider supports proper registration, consent management, and traffic controls.
For a small shop sending occasional, permission-based promotional messages, maintaining a single number may provide a simpler customer experience.
However, as marketing volume increases, separating promotional and operational messaging becomes worth considering.
The more your shop depends on text messaging for daily operations, the more important it is to evaluate the risks of combining service and promotional traffic.
For shops using automated customer journeys, declined service follow-ups, reactivation campaigns, and other high-volume marketing programs, a dedicated marketing number may provide valuable operational separation.
Common Email and SMS Warming Mistakes
Even with the right technology, poor sending practices can create deliverability problems.
1. Sending to Your Entire Customer Database Immediately
A large customer database is valuable, but that doesn’t mean every customer should receive a marketing message at the same time.
Start with eligible, engaged customers and expand gradually when appropriate.
2. Using Old or Unverified Contact Information
Customer contact information changes over time.
Old email addresses can generate bounces, while outdated phone numbers may belong to someone who never agreed to receive your messages.
Keeping customer records accurate is an important part of maintaining deliverability.
3. Treating Transactional and Marketing Messages the Same
Appointment confirmations and promotional offers serve different purposes and may require different permissions.
Your marketing platform should recognize these differences and apply the appropriate communication rules.
4. Ignoring Unsubscribes and Opt-Outs
Continuing to message customers after they opt out can create compliance problems and damage sender reputation.
Unsubscribe and STOP requests should be processed promptly and consistently across relevant campaigns.
5. Increasing Sending Volume Too Quickly
Sudden increases in email volume can trigger additional scrutiny from mailbox providers, particularly when a domain has little sending history.
For SMS, sending beyond approved throughput or daily limits can result in failed or delayed messages.
Volume should be managed according to each channel’s requirements.
6. Using Your Primary Business Communication Channels for High-Volume Marketing
Sending promotional email from the same domain used for everyday business correspondence or using your main service phone number for high-volume marketing can create unnecessary risk.
Separating marketing communication from essential operational messaging can help protect the channels your shop depends on.
7. Assuming Warming Is a One-Time Task
Completing an initial warm-up doesn’t mean deliverability problems can never happen again.
Spam complaints, poor list quality, inconsistent sending behavior, and technical configuration changes can affect established senders.
Maintaining a positive reputation requires ongoing attention.
How a CRM Helps Protect Marketing Deliverability
Email and SMS warming can become complicated when a shop is managing multiple campaigns, communication channels, and customer segments.
A well-designed automotive CRM can make this easier by connecting customer data, marketing automation, consent management, and delivery reporting.
For example, a CRM can help shops:
- Segment customers intelligently: Identify appropriate audiences based on service history, engagement, and communication preferences.
- Manage sending volume: Introduce email campaigns gradually and respect SMS sending limits.
- Track customer permissions: Maintain consent records and automatically honor opt-out requests.
- Monitor deliverability: Identify bounces, complaints, filtering, and other problems that affect communication.
- Improve message relevance: Send service recommendations and offers based on actual customer needs instead of generic mass promotions.
- Separate communication channels: Help manage promotional and operational messaging independently where appropriate.
With automated customer journeys, shops can move beyond sending the same promotion to everyone and instead communicate based on service history, customer behavior, and specific opportunities to bring customers back.
At HiBeam, we believe effective customer communication starts with understanding the customer.
A customer who purchased tires three years ago may be approaching another replacement. A customer who declined a recommended repair may need a timely follow-up. Another customer may be showing signs of becoming less likely to return.
These situations create opportunities for relevant, personalized communication.
But even the most relevant message has no value if it never reaches the customer.
That’s why deliverability, customer segmentation, and communication management should work together as part of a broader customer retention strategy.
Better Deliverability Is Only the Beginning
Email and SMS warming help establish the foundation for reliable customer communication. But getting a message delivered is only the first step.
The bigger opportunity is adaptive marketing, which uses customer information and behavior to determine who should receive a message, what they should receive, and when they should receive it.
Sending more messages doesn’t automatically produce better marketing results.
A shop that sends 500 timely, relevant messages to the right customers may generate more value than one that sends 5,000 generic promotions.
Successful marketing isn’t about reaching the largest possible audience. It’s about creating meaningful communication that encourages customers to return when they need service.
Just as importantly, marketing should never compromise the communication channels your shop relies on to operate.
Using a dedicated marketing email subdomain and evaluating whether a separate promotional text number makes sense can help protect those essential communications.
Build Stronger Customer Relationships With HiBeam CRM
HiBeam helps independent auto repair shops turn customer and service data into more relevant, timely marketing.
With advanced customer segmentation, adaptive marketing campaigns, automated customer journeys, and integrated communication tools, HiBeam CRM helps shops move beyond generic email and text blasts.
More Customers. Better Relationships. Higher Sales.
Discover How HiBeam CRM Can Help Grow Your Shop
Author: Chris Matson is the Founder of HiBeam and an experienced automotive business and marketing professional. Since 2009, he has owned and operated independent auto repair shops while building an automotive-focused marketing agency. Earlier in his career, he served as CFO of a broadcast television group, adding financial and business leadership experience to his hands-on automotive and marketing background. Chris writes about automotive marketing, customer retention, communication, and strategies that help repair shops grow revenue.
