Originally Posted by luckytokenz
so would you put them as high as 15% if you figure you opponents to be playin slightly better than average hands?


That is one way to go at it (by counting the hands that opponent plays) but look at this link:
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http://en.wikipedia.org/wiki/Poker_probability_(Texas_hold_%27em)
Then go down to "Probability of facing an ace with larger kicker when holding" which does not account for the ace in the flop btw. If your playing A9 with 9 people in the ring then there is a 29% chance someone got dealt a whole card that was an ace and something bigger than a 9. If your playing A9 with six people in the ring then there is a 19% chance that someone in the ring got dealt an ace with a bigger kicker (not taking the information from the flop into account which lowers it a bit).
So one way to look at it is to take the hands your opponent would play to flop that beat you and divide by the hands that they would play. And another way to keep your intuition about the probabilities sharp is just be aware of the sifting nature of these card games. Good hands get sifted through the bets and raises and bad hands get sifted out (basically a variant on the monte carlo problem).
Both ways are informative in their own way.