By Matt Harris, Co-Founder of Dyspatch

Odds are, you read an email on mobile today. Probably even a few.

Mobile is now the standard vehicle for email. A recent study showed that 54% of all emails are opened on mobile. Mobile has accounted for the majority of email opens since 2015.

Considering these facts, it’s surprising that so many emails are still not optimized for mobile. Many don’t function well or simply look terrible on the smaller screen, reflecting poorly on the sender. Consumers have little patience for emails they can’t read or interact with. Some 80% of consumers say they will delete an email if it doesn’t look good on their mobile device.

Rather than preparing a “mobile version” of your email, consider making mobile the primary version. Mobile-optimized content still looks great on a desktop and on a global level, mobile use is growing while the desktop is shrinking.

Moving to mobile-first email design doesn’t have to be a huge ordeal. Below are some of the most common mobile email gaffes. They’re also some of the easiest to fix.

1. Buttons and text are too small. The biggest difference between mobile and desktop is those small screens. Laptop screens generally range from 11 inches to 15 inches or more. Smartphone screens max out at around 5.5 inches. To work in this context, you need buttons that are large. Readers should be able to tap the buttons with their thumbs. Text, too, is often way too small for mobile. Ideally, text should be at least 15-18 px and headers should be around 22px. It’s also a good idea to set your width at 600-650 pixels.

2. Things stack weirdly. If your content isn’t optimized for mobile, readers will need to scroll horizontally to follow text off-screen or images will be cut off in strange places. That’s a bad user experience but awkwardly rendered content also reflects badly on your brand. Use a clean, single-column layout with a vertical orientation.

3. Your emails are too large, resulting in slow loading on mobile. Users expect interactive content but try to avoid too much of a good thing. Some 40% of readers will abandon a website if it doesn’t load in three seconds – email likely has a similar grace period for loading. So keep load time in mind when planning interactive elements, to make sure your customers don’t abandon them before they’re even open.

4. You use image-based text. This is a bad idea all around but you should stop doing it if for no other reason than it can take too long to load, or fail to load at all in some cases. This means your customer will never see your message. And some native email apps, like those on Windows Mobile 7 and Android, compound the problem by blocking images by default.

5. You include links that don’t work on mobile. This can happen for a variety of reasons, so prevention is key. The first step is to test that links work and load when on mobile. The second step is to ensure that any websites linked to are mobile-friendly. It would be a waste of resources to make your emails mobile friendly only to have click-throughs lead to non-mobile pages.

These mistakes might seem obvious, yet I see them over and over. The reason isn’t just that email rendering on mobile is exponentially more complex than on the web — which it most definitely is — it’s also that transactional emails tend to live in the codebase, which means keeping them up-to-date for mobile is too often a low priority. To create an optimum customer experience, that simply has to change.

That’s why best practices for email in 2018 must include testing on a wide variety of email clients, ESPs, apps, and devices. Device testing should be a non-negotiable part of your workflow, for every email you send, including your transactional emails. Testing is the best way to ensure your content will render properly no matter what device your customer uses.

Don’t forget that 54% of all emails are opened on mobile. If mobile optimization hasn’t already been a priority for your email outreach, isn’t it high time it was?

An edited version of this article originally appeared on MarTech Advisor.