Starting an email marketing program is one of the smartest things a business can do. More than half of the planet uses email, and 61% of consumers prefer to hear from brands via email.

While sending email newsletters and campaigns isn’t brain surgery, it’s easy for bad habits to slip through the back door. Here are 11 common email marketing mistakes — beware of them so that you reap the full rewards of email.

1. Not segmenting the prospective audience

The most effective strategy to boost email results is email list segmentation. This is according to 78% of marketers. It makes sense if you think about your own inbox: Aren’t you more likely to engage with an email that feels written just for you? Before sending another email, analyze customer data and use filters such as location, gender and shopping habits to segment the prospective audience.

2. Not testing emails

Hitting send on an email without testing it is like buying an expensive garment without trying it on — so many things can go wrong. An image may not load correctly, one of the links may be broken, and many other possible pitfalls. Few things are worse than knowing that an avoidable mistake was made. Test every email with your team to make sure nothing falls through the cracks.

Related: Why Automated Email Marketing Is an Essential Tool

3. Being inconsistent

Inconsistency is one of the biggest reasons people fail at anything, not just email. There are plenty of stories out there of other business owners who make great money with their emails, but here’s a key point: They show up in their customers’ inboxes regularly. Email takes time to work, so have discipline about creating a consistent schedule. It’s the only way to build engagement.

4. Bombarding people with emails

Emailing that list consistently is vital to building rapport, but consistency shouldn’t be three times per day. Prospects clearly want to hear from a business when they share their email address. However, be mindful of their time and the space that you are taking up in their inboxes. Some emails are daily by design, but never send more than one email per day.

5. Using an old email list

Holding on to customer email addresses from years ago is understandable — growing an email list is challenging. However, email data decays at an average pace of 23% annually, so you must reassess the health of your list regularly. Keeping addresses people stopped checking months — or even years — ago affects your performance.

6. Not removing invalid emails

Many entrepreneurs have no idea that bounces affect their entire email marketing campaign. When more than 2% of emails bounce back, your organization begins to look like a spammer to inbox providers. Due to this, your emails will go to spam as a result. Avoid that by validating your database quarterly. If it grows quickly, verify it more often to help your emails get to the inbox.

7. Ignoring spam complaints

Has someone reported your email as spam? Remove that person from your list immediately — they clearly don’t want to hear from you. Chances are high that if you email them again, you’ll get another complaint. That can have a dramatic impact on your email deliverability. To stay in the good graces of inbox providers, ensure that your spam complaint rate stays under 0.01%.

Related: How to Avoid Email Spam Complaints

8. Crafting emails that are too long

Writing an email to your list is exciting, right? The inbox is a great place to connect with your prospects. However, you’re not the only company popping into someone’s inbox asking for attention. Be mindful of how many words you use and convey your thoughts succinctly. For in-depth topics, write a short blurb and link to an article instead.

9. An intimidating layout

Let’s say that your newsletter is longer than typical marketing emails. That’s alright as long as it’s engaging. Aside from making every line count, also try to lay out your content in a way that’s easy to digest. Use spacing and images to break up big chunks of text and make longer emails less intimidating.

10. Not including preview text

Sometimes it’s not the headline that gets someone to click on an article — it’s the subheading. The same goes for email. If your subject line isn’t enticing enough to make people click, the preview text can make an email irresistible. Add that bit of copy to every email and also test emojis in your preheader text to see how it affects your engagement rate.

Related: 5 Simple Tweaks for Better Email Deliverability

11. Failing to reply to your customers

Getting a reply from one of your subscribers is email marketing gold. Whether they’re writing back to share feedback or ask a question, it shows they care and want to further communicate with you. What’s more, replies are good for email deliverability as inbox providers see them as a sign of trust. Ensure you respond to all emails. Ignoring a message from a customer has ripple effects on your brand.

If you’re guilty of these email marketing mistakes, know that you’re not alone. I run an email optimization platform, and my team and I have had some email blunders, too. We’ve learned from them and started seeing better results through the years. You’ll experience that as well when you pay attention to these details and fix errors before they can cause damage.