Some people just don’t care about design, industrial or otherwise. If you are the kind of person who likes their computer sans design, then dude, you’re getting a Dell. When Dell was using that as a tagline, it felt more like a harsh threat to naughty kids. Back in the day, there were also many PC fans that hated Apple products, in part, because they focused so much on design.

Then there were and are the Apple devotees who only use those products because the company has such a focus on design for both the hardware and software. Apple fans are somewhat notorious for being hard on products that ship with poor design, even if they perform well enough.

Recently, LG made a line of monitors exclusively for Apple MacBooks Pro in conjunction with Apple. The community largely rejected them and panned them on the basis that they were ugly—not the picture, but the monitor itself. The fact that some models also suffered for a technical issue was extra.

If you are making an app for users of high-end smartphones, you have to focus on the design of your app. If you don’t, that app will fail. The only exception would be if that app is so unique and so essential that people just can’t do without it. In that case, they will buy it and use it, but will also endlessly complain about it. Here is what you need to know about creating apps and accessories for people who care about design:

Smartphone Cases
At this moment, about a million people are buying an iPhone 8 Plus. When they take it out of the box, they are going to marvel at Apple’s design prowess. They will handle it, flip it over, rub a finger across the shiny Apple logo, sigh, then slap a case on it. They don’t want to put a case on it. They have to for protection. Still, they will not put an ugly case on a phone the spent $800 for.

You need to make iPhone 8 plus cases worthy of the iPhone. Even a thick and heavy protective case needs to have style. You need to minimize logos and other writing. This product belongs to the end-user. It is not a platform for free advertising. Smartphone accessories ought to accentuate the smartphone, not the accessory.

Smartphone Apps
There is great value in aesthetically appealing smartphone apps. Aesthetic appeal is about more than just looking good. It is about working well with the design of the phone. The Apple Watch is a square watch with rounded corners. You do not want to tout a round app you made for a different smartwatch. Even if you could fit that round peg into the square hole, you wouldn’t want to, no matter how many design awards it won.

The iPhone X is not the first phone with a prominent notch at the top. But it is the most influential. iPhone app makers have to redesign their apps to work with the iPhone X if they want the wealthiest slice of the wealthiest people to care about their app. Even google has embraced the notch. So no matter which platform you write for, you have to design your app to work with rather than against special design elements of the phone.

Smartphone Accessibility
All smartphone platforms have some type of accessibility built into their operating systems. What developers mostly need to do is stay out of the way of those features. You get them for free in your app by following the guidelines. At the very least, you should test your designs against the accessibility features to be sure that the people with disabilities who use smartphones can also use your app.

On iOS, your app needs to be compatible with VoiceOver: the built-in screen reader. It needs to work with Apple’s dynamic font system that allows the user to adjust the size of fonts. And there should be no hidden code that interferes with the Speak Screen function that enables a person to have the screen read to them with the downward swipe of two fingers from the top of the screen.

Cases, apps, and accessibility are all a part of the same design conversation. Design is both how it works and how it looks. Good design can’t have one without the other.