Anytime someone has 3-5 Big blinds left and they catch a decent hand they should to go for it. I do notice a lot of players are so afraid of getting called they push. This almost always backfires on them.
You cannot let yourself get down that low. Even if you catch a hand, get called, and doubled up your stack is still crap and your still in the same situation. That low you risk getting sucked out on if you do have a hand anyway.
Gotta start looking for a spot when down to ~7-8 BB's at worst to shove and either get the blinds, double up, or bust. CARDS DO NOT MATTER. On loose tables where its impossible to be first in, when UTG makes sure I am. Sure people look at me like I am a donk shoving 35o UTG and sucking out against a high PP, but I rather suck out or bust than be the dead one everyone is looking to bust out due to my stack being so small after getting hit with the blinds. Especially in the later stages with high blinds and ante's. I have stole my way from a 50k stack to a 300k+ stack (from short stack to 2nd chip leader) with the BB being 10k and never seeing a flop before. Every time they fold, your stack becomes more and more of a threat to theirs, so then they have to have even stronger hands to call, while I am choosing stronger and stronger hands to do it with.
I say this in reference to large MTT's where all the $$ is on the FT so you want to get to it, and folding down to 3-5 bb's waiting for good hands alone will not get you there.