Too many to count.
The underlying factor that played the most role was whether or not it was a "referral". If a woman came to me because one of her girlfriends told her I was packing then it was super-easy and we were in the sack within 30 minutes or less, especially if we meshed really well right off the bat. If it was a non-referral then it would come down to how horny I was (or her for that matter) and how fast we could hit it off to the point of a minimum level of "trust" that neither of us were crazy-people and that we were healthy enough to have sex without any medical regrets the next day or next week.