This is a discussion on should or should not shove? within the online poker forums, in the Tournament Poker section; how many times did you read that question?
Its knowledge by all that about 10-12bb we should be in a alert situation where we are
Way too short to be playing postflop with 10-12, even below 20 its difficult.
25th July 2017, 7:05 AM
Andrei Korolev 
Poker at: Poker Stars
It's hard to play preflop and postflop later,and there is only two options: fold or Allin.
25th July 2017, 7:31 AM
re: Poker & should or should not shove?
The main idea is that there is a range of hands you can profitably shove when first into the pot given the number of players behind you and the amount of big blinds you have.
You don't want to wait too long because if you get too low the other players will be more likely to call you (less fold equity). With the antes, SB, and BB the pot will become bigger in relation to your stack, essentially players will have better pot odds.
While this is a good thing when you pick up a big hand, more often than not, you will run out of chips before ever picking up that monster hand and will have missed many profitable opportunities in the mean time.
If you have no profitable opportunities to play with 10-12 big blinds, sure, keep waiting, but you will have to find a spot the next orbit or risk getting to the point where you have limited fold equity.
You can stay alive by stealing the blinds and antes once a round until you get a big hand and hopefully double-up, but that's not the only goal since winning the blinds and antes are a good result a lot of the time with a short stack.
If you play a lot of tournaments you will want to study and get to know what cards to you can go all-in with at various stack sizes, eventually it will become second nature.
Good luck to you!
25th July 2017, 7:46 AM
Poker at: Pokerstars
as dougpkr mentioned the fold equity is he main reason.
But it's not always that simple.