Normally I will start it up around 7-8am and then go to work with it set to hearth when bags are full. I come home to see it's farmed for 4-5 hrs and then closed out wow and that works perfectly for me.
I have left it on over night a few times with mail to alt and had no issues that way as well but it's a little bit more worrisome with that long of a session for me.