The Costly Email Mistake Too Many Founders Make — and How to Avoid It

There’s a reason every website you visit wants your email address: it’s the most valuable type of contact info in the digital world. Last year, email marketing revenue surpassed $9.5 billion, and by 2028, it’s projected to reach $18.9 billion.

But here’s where so many founders get it wrong: they treat email like a loudspeaker. Build or buy a list, send a “blast,” and repeat whenever you want to make more sales. Only email doesn’t work like that — at least, not if you want to connect with people and see your revenue increase. Your email list isn’t just a collection of email addresses. It’s a living system, and when you neglect it, your sender reputation suffers.

Related: Don’t Sleep on Email Marketing — Here’s Why It’s Still Your Business’s Most Powerful Tool

What taints your email sender reputation

Every email sender has a reputation with inbox providers – services like Google, Yahoo or Outlook that make email communication possible. That reputation helps their algorithms determine whether an email should go to the inbox or the spam folder.

In simple terms, it’s like your email trust score. The better it is, the more likely your messages will reach your audience. The worse it gets, the harder it becomes to land anywhere near the inbox.

Unfortunately, many well-meaning founders damage their reputation without even realizing it. Here are some of the common mistakes they make:

Buying or scraping listsNever cleaning or validating email addressesSkipping email warmup altogether

Whenever you send an email, you’re building – or tarnishing – your reputation with email providers. And once that reputation is damaged, fixing it is a lot harder than protecting it in the first place.

So, what can you do today to improve and maintain a strong sender reputation and get your emails into the inbox? Follow this checklist below, and your email marketing will become one of the most reliable channels in your business.

Use your own email list

Purchasing a list of contacts and dumping it into your CRM or email platform may feel like a quick win, but it almost always backfires. I’ve seen countless business leaders take this shortcut and pay the price – bounces, spam complaints and dismal engagement.

To reap the benefits of email marketing, build and nurture your own email list. It takes more effort, but the results are real and sustainable.

Make sure everyone opts in

Building your own email list doesn’t mean you can simply add people to it. Customers and prospects need to subscribe to your emails and grant you explicit permission to reach out. It might take longer to grow your list this way, but the payoff is huge: higher engagement, better deliverability and a list full of people who want to hear from you.

Warm up your domain and IP

Many founders get so excited about sending that first email that they skip a crucial step: warming up their domain and IP. That can tank your email deliverability before you even get started.

Email warmup is closely tied to your sender reputation:

If you’ve never sent a mass email, reaching out to thousands of people out of the gate is a huge red flag to email providers.Instead, start slowly. Increase your volume gradually to build trust with Gmail, Outlook, Yahoo and other providers. Or find a good email warm-up tool.Even regular senders can benefit from warming up their emails, especially after switching platforms or letting their lists go cold. It helps re-establish credibility and improve inbox placement.

Check your contacts regularly

Even if everyone on your list has opted in, that doesn’t mean their email address is still valid or that they’re still clicking on your emails. An astounding 28% of the average database degrades every year. People change jobs, abandon their inboxes or mark your messages as spam if they’re no longer interested.

Regular list pruning helps you filter out:

Email providers are watching how your list behaves. High bounce rates, spam complaints and low click rates affect your sender reputation. Clean your list at least once a quarter — or more often if you send campaigns weekly.

Look at the big picture

Open rates used to be the end-all-be-all of email marketing. But thanks to privacy updates and stricter data regulations, those numbers are less reliable than ever.

If you want a true picture of how your emails are performing, shift your focus to metrics that offer more in-depth insights:

Click-through rates — are people taking action?Bounce rates — could your list be outdated?Spam complaints — are your messages annoying your audience?Engagement over time — are people clicking or tuning you out?

These numbers reveal how your audience feels about your emails and whether inbox providers perceive you as trustworthy. Focus on long-term engagement, not just one-off opens.

Related: 8 Simple Email Marketing Tips to Improve Your Open and Click Through Rates

Think like your subscriber

Before you send your next email, stop and ask: Would I open this? Would I care?

So many brands write for themselves, not for the person on the other side of the screen. But if you want people to engage, you have to earn their attention. That means being clear, consistent and genuinely helpful.

Email marketing isn’t dead, but lazy email marketing definitely is.

Treat your list with the same respect you’d want in your own inbox. Build trust over time. Show up regularly. Say something worth reading. That’s how you stay out of spam — and in business.