When is it ok to say "yes"?

At what point in the dating process is it "ok" to sleep with a man? is there a set time limit? I mean as a woman we have this constant battle in our head...

"if i sleep with him too soon he will think i am easy..."

"if i hold out for too long he will get bored and look elsewhere..."

"i want to do it but i feel that i shouldnt..."

"what if i do it, then learn thats all he wanted..."

"how do i know if he likes me for me..."

"i dont want to devalue the meaning of sex by acting to quick..."

In our society, sex and dating have become synonomous with one another. Rarely do you find a couple that is "dating" and not having sex. Have we as a society devalued the precious interaction known as sex? Have we transformed it from a priveledge to an expectation? Do we still utilize the same discretion in selecting our sexual partners? Should I feel guilty after each sexual encounter?

Do men have these same concerns, or are their brains just wired differently? Do they even think about their "numbers"? Do they ever turn down sex for fear of what the woman might think of them? Do they hold out to make things more meaningful? I seriously doubt it...

But then the question becomes, does holding out actually make sex more meaningful? My most successful relationship, which lasted for almost three years...started with sex on the first date. Going to show that early sex is not always detrimental. But it just seems like so many men are just looking for sex, so i am constantly concerned that i am just another notch on their belt. and thats a lowly feeling. especially since the man did such a good job of convincing me that i was more than an easy lay. after its all said and done, thats when you learn whether he was worth it or not. and if he was...you got lucky. and if he wasnt? well, its too late for that.

How does a woman know whether she is just a notch, or a genuine romantic interest? How does she know when its ok to say "yes"? Can she know? Or does she just continue to roll the dice and hope...?