It takes some people more time to act then others, but there is really not a whole lot of reasoning behind this in my opinion. You should already know what your going to do a few seconds into the decision, over thinking is a bad thing to do, you end up making more mistakes then your thought process of a few seconds. If a person knows the game at all, you should most likely instantly know what the right play is, and go with your first gut instinct. Acting instantly is not a good move either, easier to pick up a read on a player that almost acts instantaneously. I thought when watching live poker on t.v the that the players almost waited forever to act for a little t.v time and not to look to fishy with there decisions. That being said you should always roughly within seconds take the same amount of time you always do, or it might be easier to gather a read for the other players. There is really no reason to take a whole lot of time unless you area faced with a decision for all your chips, even then to much time and overthinking is not a great thing to do. I think a 30 second shot clock per hand is a great idea for most tournaments, with optional 15 to 30 second cards you can play if need be, because sometimes you need just a liiitttlllleee more time for a good decision, but not a whole lot.