Marco Arment walks through the redesign of the Apple Watch version of his popular (and excellent) podcast player, Overcast:

I originally designed the Apple Watch app for my podcast player, Overcast, with a scaled-down version of the iPhone app’s structure.

This seemed like a sensible adaptation of my iOS app to the Apple Watch. In practice, it sucked.

I’m a big fan of Overcast (and I’ve also used both versions of the app), and the new design is a much better fit for the way I use it. The whole article is worth reading to see all the detailed reasoning behind all of the changes.

On the phone, apps are designed for interactions and activities that are generally a minimum of two or three seconds long. On the watch, that’s usually the maximum amount of time you want an interaction with your app to take. These constraints result in very different designs on each platform.

This is something I realized very quickly when designing the Apple Watch version of DanceMaster. In fact, the new design of the Overcast watch app is structurally very similar to the design of the DanceMaster watch app— the app is basically a one-screen remote control plus status display for the current state of the phone app, with advanced functions and navigation available from a force touch menu.

Although the constraints that lead to these designs are driven primarily by the situation in which the device is used, the performance characteristics of the APIs currently available to third party app developers really punish suboptimal designs. It is very difficult to produce a third-party app that is a truly glanceable and as quick to interact with as the watch face itself. Behind the scenes, there are all kinds of ways that we can try to optimize the performance of the app, but there are some watch app behaviors that we can’t currently do anything about. I’m very interested to see what kinds of native support for app development will be announced next week at WWDC, because there are many ways that both of our apps could be even better.