the reason that it can be bad turning on and off is because the com board heats and cools this causes expansion and compression cuasing faults in the mother board/com board. laeving it on is ok but like they said don't let it overheat my kids are bad for it to by putting things on top of them.It's the same with most materials if they're at a constant heat they're fine but change the temp several times like an engine they will break down over time