Should we turn machine off for summer break?

Yes, infact we would recommend you simply unlplug the machine if you won't be using it for an extended period of time (such as summer or winter break).

*This won't hurt anything, when you turn the machine back on everything will pickup right where you left off. No need to redo any settings or anything like that. Unplugging the machine will actually help safe-gaurd you against any storms/power surges your location may have during your "break". There's no point leaving it on if no-one will be using it.