User Interface Platforms

Interface guidelines are important for multiple reasons:

• Ensuring consistency between designers
• Matching users' expectations
• Maintaining a visually-distinct brand

These can be on a small scale, such as a list of fonts and colors, or a fully-established design system that covers everything from looks to functionality.

Follow the Leader

People tend to be unaware of the navigation experience in an app unless it doesn’t meet their expectations. Your job is to implement navigation in a way that supports the structure and purpose of your app without calling attention to itself.

— Apple, "Human Interface Guidelines: Navigation"

Users expect things to work a certain way on their devices: without even realizing it, muscle memory is created as users navigate other apps. As a designer, it can be difficult to balance the need for creativity with the necessity of familiarity. You might be able to create an awesome menu and navigational system, but it's no good if the user can't figure out how to get around. Unless you have a good reason and the capabilities to test your design, sometimes it is best to follow interface conventions and avoid "reinventing the wheel".

Adapting Between Platforms

If you’ve created an app on one platform, this is most of what you need to know to “translate” it for the other platform. But! – these are guidelines, and basically everything I’ll say is contradicted somewhere, even by Apple/Google themselves. This is about translating “iOS thinking” to “Android thinking” and vice versa.

— Erik D. Kennedy via Learn UI Design, "iOS vs. Android App UI Design: The Complete Guide"

Any organization or company large enough to have a huge list of platform guidelines a) has spent some time on them, and b) is motivated to make effective choices for their audience. "Best practices" tend to follow across platforms, such as creating accessible designs, making sure it's easy to navigate through your app, or ensuring that users can differentiate groups of information. How they do it, though, can vary from platform to platform.