gator: tom and cue are right about position, and also relative stacks, blinds, and hand selection. there are many variables to consider and how they add up to equal a decision to play or fold. i will fold a normally strong hand early and play a normally weak hand late.
there are other things to consider that nobody is saying though, and i lt bugs me when folks say "ain't gettin no good cards" as a reason not to play because the actual cards are probably less than half the battle. remember, nobody knows which cards you have unless they pay to see them or you voluntarily show them. so if you know or have a good idea about your opponents, like what hands they play or how they play certain hands or how quick they will abandon their hand if a scare card shows on the board, then you don't need good cards. you can play against their fears or suspicions or lack of conviction, or offer them poor pot odds to continue the hand. the worst opponents to play against are the ones who don't know how dumb their decisions are because they will often draw out on you. the good players will often do what they are 'supposed' to do in a given situation. the great players are those that spot the good players and make it convenient for them to make the 'correct' decision. play the player not the cards.
i actually play rather predictably once you know what it is i am doing. but there is a formula for winning these types of sit-and-go single table tourneys, and i like to think a have figured out a way to make it profitable for me. that is bad because it makes me predictable which can be exploited. so i deliberately introduce variance in my game to counter the predictability.
there are certain hands i will always play and certain hands i will never play (unless i'm in the blinds in an unraised pot). so to introduce variance i choose a hand at the start of the game i will play no matter what, every time i get dealt it. and i am going to play it like i got the nuts. could be 83 suited or 6T offsuit or Q5. when i see that hand i trick my brain into thinking it is pocket rockets and i play it that way, i believe it is aces, i know it is aces.
even if i lose with that hand that particular night, and i do alot, then it is still worth it if the intentional 'unpredictability' affords me room to move (and get callers - that dumb donk will play anything and gets sooo lucky) when later i actually do have a hand.
there are many ways to skin this poker cat from perfect accountant machine to cold hearted gunslinger. if you play long enough will find your way gator.