I never would fold K-K preflop because the other people most likely have an ace or a pocket pair, so if no ace comes you probably have about an 80% chance of winning. No ace will come like 70% of the time but assuming at least one of your opponents has an ace u'll be getting very good pot odds, about 56% pot odds on tripling up (With the exception of the maybe 10% of the time someone has Aces). Maybe i wouldnt do it if you were in a MTT and only a couple people away from making it in the money, but aside from that I personally would do it everytime.

(note the statistics in the are not exact but they should be very close)