mobile - Is shaking a device to refresh an accepted behavior?

I have an app that displays downloaded information that is cached. I could use valuable space to include a button that is used to re-download the information, or I could simply add a "shake the device to refresh" feature.

My question is, do I have to include some instructions about shaking the device to refresh? Or is it such a common feature that users will expect it?

Answer

Don't rely on shaking as the only way of selecting any common action. The exception is novelty apps like whips or throwing dice.

For other apps it is poor UX as it:

1. Is uncommon behaviour for many users, as most apps (sanely) don't use this action.


2. Has poor discoverability as there is no cue on the screen letting you know how to use it. There may be an initial tutorial screen, but that isn't visible when using it.


3. Often requires a grip change to do it, and is impossible to use when your device is on a flat surface.


4. Poor accessibility for anyone using an assistive device.


5. Breaks your visual continuity as you can't really watch what is happening while you shake it.


6. Has calibration issues. You often also have to shake it a few times for it to trigger if it's insensitive. If it's sensitive, you then can have it trigger when you aren't trying to shake it.


7. I (and many others) will uninstall your app and give you a 1 star review if I have to shake it to perform a common action.

If you want to have shake to refresh, fine. But you should also include something sane like pull to refresh, or a simple refresh button.