Why do I need to restart my Time Capsule 3TB so often?

Any ideas why I need to restart my Time Capsule 3TB so often? At least once a week, it becomes unresponsive - my iOS devices can no longer connect to it (though interestingly, my Apple TV usually maintains its connection).

The only way to restore my connections to the Time Capsule are to restart it, usually by unplugging it. (I'd much rather restart it using AirPort Utility, but the Time Capsule is unresponsive there as well.)

This is a relatively new Time Capsule 3TB purchased in January 2015. It is running version 7.7.3, which I believe means it's up-to-date.

Any idea why my Time Capsule is doing this? This behavior has become so annoying that I'm considering using a non-Apple router for the first time in years!