I was in a band with my brother and sister which invariably meant I lived with them. It didn't actually work quite as well for practising because you can practise anytime you tend to put it off. Whereas in other bands I've been in where we have to book rehearsal time you feel like you have more of an obligation to practise, and when you do you put in more time and work harder because you are paying for it and its he only time you can practise that week or whatever. That said if you are really great friends with the people in your band and you are all pretty obsessed with it living together would be great.