Yeah, my general rule is "at least 10x, more if I think the player is less likely to pay off." Certain people are of that exact type that they ONLY 3-bet with big pairs and NEVER fold big pairs after the flop; those people you really only need about 10x in my book. Same deal with any short stack because they are generally more pot-committed in their own minds. But those are rarer cases. Against normal players I aim for about 15x. Here I'm getting about 15x just from the guy who reraised (who I also have position on, glory hallelujah, and who I know will put a lot of money in when he probably shouldn't) and there's gravy in the form of another player as well. I think folding this preflop is way, way too nitty.