In general, players tend to overplay pocket Aces early in a tournament. When the stacks are still very deep (100+ big blinds), you probably shouldn’t be getting all-in with just a pair of Aces at any point during the hand unless it is blatantly obvious that your opponent has something like a pair of Kings that they won’t fold.
The key to playing Aces early in a tournament is pot control. You don’t want to put yourself in a position to have to call off your entire stack with “just” Aces (unless it’s preflop, then by all means, go for it!)
Consider the following hand:
You make a raise with pocket Aces and a player in the small blind calls. The flop comes Queen-Ten-Seven. He checks and you make roughly a pot sized bet. He calls. The turn is an Eight.
Immediately after seeing that card, your focus should be on getting one and only one bet in on the turn. What does that mean? It means if he bets, you “just” call, and if he checks you can bet but consider folding to a raise. This concept is known as “pot control”. Right now the board is Queen-Ten-Eight-Seven, which is actually a pretty scary board for when you’re holding pocket Aces. There are a lot of possible two pair, straight and straight draw hands that should bring you some pause. You don’t want to get into a raising war on a board like this and wind up dumping off your entire stack so early in the tournament to someone holding Queen-Ten.
Let’s consider one more example:
You raise with Aces and two players call. The flop is Six-Four-Two. They both check and you make a fairly large bet. One player folds but another player raises you. This should come across as very scary to you. You definitely do not want to re-raise them. There is very little value in that. At the same time, folding is probably way too tight. Yes, it looks like he could possibly have a set, but let’s just call and see what he does on the turn.
You call and the turn comes an Eight. Your opponent leads out for a very large bet again. This is another situation where you’re either going to fold or call, not raise. One idea would be to call and see what happens on the river. If he fires another very large bet on the river, maybe you let go of the Aces. If he checks, it’s quite possible he has something like pocket Nines, but you should still probably check behind since the pot is already big enough and you don’t want to trap yourself.
This article should give you an idea of the mindset to have when playing pocket Aces early in a tournament. The idea is to control the pot size and not get carried away by playing for all of your chips.