If I'm looking for long term: not at all.
Everyone's different, but for me, I'm not willing to be intimate until I have some commitment.
When I'm in a new, unofficial relationship, I try to think "will I regret doing x with this individual if it turns out he isn't interested in something long term?" If I get to feeling that I will be upset/too attached if I do something without the commitment, I won't do it.
I know I will want commitment and other things, because I'm not strong (or insert proper adjective) enough to separate sex from it.