[EWillers]

I know the math guys can answer this much more precisely, but. . .

100K minimum I think is quite a bit too high. It depends, of course, on how accurate you want your rate to be. But in the time it takes to accumulate 100k hands (unless you're playing 2 or 3k a day) I imagine that the "goodness" of the games will have varied enough over the time the hands are played to outweigh any more precision in the winrate created by playing 100k hands vs. say, 20k hands.

I think that it's a scale. The smaller the # of hands, the more off your winrate may be. As the # of hands goes up, the more accurate the winrate tends to become. Beware of comparing hands from 6 months ago to hands played now tho. 1) You may have gotten better (or worse) and 2) (more likely) the games are noticably better or worse now than they were 6 months ago.

Bottom line, in my opinion, 10k or so will give you a pretty good indication and 20-30k will give you solid enough of a win rate to feel comfortable about (assuming the level of play remains relatively constant--big assumptioin).