When my 522 was first installed (6 weeks ago) I was experiencing various lockups, needs for reboot, strange behavior, etc. I was leaving it on 24x7.
That went on for about my first week with the unit. Then I started turning it off every night before bed (both tuners). I've missed a few nightly turn-offs, but I've been remembering 98% of the time.
Guess what? No more lockups. No need to reboot. Everything has just been running much smoother. Cause and effect, or coincidence? You can make your own decision. I'm just reporting what I've experienced.