Hypothetical situation:

You've met someone at a social gathering and get along well but one of you has to leave. So you are both strangers at this point. Before going you exchange numbers. How soon after the event do you call?

Follow up: What if this person lives a bit far away? An acceptable distance such as a one to two hour drive but not close enough that you could make the trip everyday. Is it worth pursuing?

I'd appreciate answers from both genders.

Edit for mod: I'm 25.