Waiting, a good or bad idea?

Usually when I like a guy I pretty much sleep with them pretty quickly but every time I've done that they've left after getting what they wanted. I met a guy on Friday and he asked me to go home with him but I told him I want to wait for about 3 months. I got out of a horrible relationship a while ago and wasn't planning on being with anyone for a while but me and this guy have been overly flirty so it feels hard to wait. I mean this guy seems really nice, different from all the others but I'm torn between wanting to and waiting the 3 months. 
How long do people usually wait? Does making them wait longer increase the chance of partners staying after getting what they want? Does it make a difference?