When you play a hand like 22 you are in need of making trips when the flop cames, the chances of this happening are 8 to 1 against. So to play this hand in a profitable way you need very good pot odds. The ideal scenario for this types of hands is when you are on the button and many people just limped into the pot, in this case you have yo invest few chips to win an already big pot.
In the early stages of a tournament and facing a raise i'll just fold this hand.
pot odds arnt the issue here.. its implied odds.
The pot odds will never give you the 8:1 needed to call
BUT implied odds may be 10:1 or even higher in this situation (especially against an early raiser)
you have to believe that you will earn 10:1 if you hit a set (if not then its not worth a call)
but if you can put the guy firmly on say AA, KK, AK and know that he will bet out big (preferably all in) then see the flop because if you hit the set and the odds ofthat are around 8:1 then a 10:1 payout makes it worth a call.
Calculating implied odds isnt easy though.. most will take the shortest chip stack in the situation (either yours or his) then divide that by the bet.
BUT as I said before, you have to be confident that he will push if he hits otherwise its not worth it.