Do you know this?
As you practice, you should find a particular note all over your instrument.
Or you have to play the major scale in all different keys.
But you always think of the same notes and keys?

For me this was annoying enough to develop an app for it.
This app generates random notes for you and you don't have to worry about which note is still missing or which key would make sense next.

Works perfectly on the Apple Watch too!