I'm a tightish player, early on in a tournament I'm more likely to try and see a flop with AK, that means calling raises, not 3-betting or 4-betting PF. If I hit then I can decide what to do, but most likely I'm going to go all in if I can, extenuating circumstances aside.
Later in a tournament I play a bit more cautiously. I'm still raising with AK from any position, but I'm less likely to call all ins and large raises depending on my stack size. If I'm medium stacked I'm especially cautious. AK is the ultimate coinflip hand, I always assume its a coinflip, its easier that way rather than trying to place my opponent on a pocket pair like 99+ or a weaker ace like AJ or AQ, many times they're playing either equally.
Its basically a decision for my tournament life, do I have enough chips to fold and pick a better spot? Will my fold equity be too depleted after folding, or will it be depleted in a few rounds of blinds and antes? How much would I have left if I did make the call? If I'm medium stacked, not alot unless my opponent is a short stack. Basically, if I have the chipstack and its too much to call, I'm folding PF. If I can call the raise without giving up too much, I will.
That's basically my medium stacked AK strategy... for short stacked its an instacall anytime, for a big stack it depends how big my stack is, and my opponent. A big stack with large blinds and antes can disappear really fast and turn into a medium or short stack if one gets too spewy.
AK is probably one of the hardest hands to play correctly. Pocket pairs are easy enough, because when overcards come on the flop you can fold. I'm naturally cautious with weaker aces like AJ or AQ, but they have many of the same problems as AK. AA, KK, and QQ are easy, shove and complain about a cold deck if someone beats you or turns over a higher pocket pair. Only thing that might be worse than AK to play is JJ, but if you're tight like me, you play it like 88 or 99 anyways, flop a set and fold to reraises if theres overcards on the board.