I think around 2 dates will give you a good idea. 2 weeks ago I had a date, which I didn't think went very well. I think the setting and time limit didn't help either (or add in the fact I was kinda hung up on a previous guy I dated).

I decided that date was enough for me. He called me this weekend and we went out again. The 2nd date was so much better. We got into some good conversation. There was more physical attraction (on my behalf) this time around.