We all know that sometimes a device reboot fixes stuff, but Google would never admit to that. Android is supposed to run constantly and keep things in order as it's designed to, but the new Device Assist app finally lays all the cards on the table. The top suggestion (and for some, the only suggestion) is reboot your phone. Dammit, Google.
Device Assist is supposed to offer suggestions on fixing potential issues with your Nexus, GPE, or Android One device. Some phones don't list any actions, some have warnings about display brightness, and other recommend a reboot. If you see the reboot advice in Device Assist, tapping on it tells you that rebooting gives your device a "fresh start." And yet, there's still no reboot option in stock Android's power menu, because you shouldn't need it, right? It's even more bare as of Lollipop.
It seems to vary from one device to the next what it tells you, but the reboot advice seems a little too self-aware for Google. You wouldn't expect Google to admit to this particular weakness. What's next? "It looks like Google Play Services is causing wakelocks. Maybe you should turn off location reporting."