@Anonymous User Welcome to the community. There's no need to turn it off at night unless you want to (some people prefer to turn it off if it's not being used or to reduce radio emissions at night, however it's designed to be left on all the time and especially for the first couple of weeks after setting it up it's best to leave it on all the time).
The hub will run warm if it's under heavy load (lots of users connected or heavy streaming) and especially so given the high temperatures we are having at the moment. Most of the ventilation holes are on the bottom so don't place it on carpet or soft surfaces, and try and place it in an open space away from other sources of heat rather than in a cupboard etc.
Unless you get issues with the hub rebooting or not working then the fact it feels quite warm isn't anything to worry about.
NOW are looking for users to join their Customer Feedback Group and help improve the service. If you're interested read more here and sign up.