Who am I working with? Am I comfortable with those same people having free access to my person and belongings while I sleep?
Do I trust these folks not to do something stupid that could damage the capital while partying? (I once had somebody spill a beer into an SGI workstation because we were using an apartment as an office, and one of our dudes threw a party.)
Can we deal with the weird interpersonal dynamics that spring up in a group of mixed sexes that is also collaborating on a business--presumably the same one paying rent?
Do I have a place I can go to to get away from work/home if needed on a reliable basis? Is it going to cost me all my money?