[Silent A]

[ QUOTE ]
I figured that the implied odds for filling up were just not there. If he had more behind him, I would have called the 15 and hoped for the board to pair so that I could stack him. Is that reasonable?

[/ QUOTE ]

General rule of thumb : on the turn, with a set against an obvious flush or straight, villain has to have slightly more left behind than he just bet (assuming he pot bets it) to barely have enough odds in the best possible situation.

Here, since he bet $15.20, he must have a bit over $15.20 left to give you the absolute minimum implied odds to call (i.e. if neither of you hold any of your outs and rake is a non-issue).

However, since he'll sometimes be holding some of your outs, and the rake is significant at these stakes, you actually want him to have about 1.5 times left over (i.e. enough to call a 1/2 pot bet on the river). And that still assumes he always calls on the river.

And that minimum 1.5 increases to 2.0 and 2.5 if you hold 1 or 2 of your own outs.