Most Helpful Guy
Depends. If you can avoid it, do so, because that makes it easier for both of you to handle the breakup and the first few weeks after. However, if that causes you to hang out and kiss and sleep with your girlfriend for a week when you know you are going to break up with them, that can be pretty harsh as well and might actually make the breakup worse for both of you, should they find out.
Most Helpful Girl
If they are abusing you then sure. Anything it takes to get out of the relationship asap. But if it can wait a few days then wait. It isn't fair to do that. Those few days are hard enough as it is and it is an emotional time already.