Big pots early in tourneys

[Snarf]

Often early in tourneys I'll play good hands more passively than I would later in tourneys - using the classic logic, the risk of losing chips isn't worth the reward of gaining. My basic question is this: How strong of a hand do you need - POST FLOP - in relation to your opponents hand to get all your chips in the center early in a tourney? What % of a favorite do you need to be win the hand? OR how many outs (pending runner runner) would you need to avoid to make it worthwhile?

Lets say an unknown opponent is pushing back at you hard when have a premium holding. If you figure to have the best hand better than 90% of the time. Do you ever fold to avoid the risks associated with busting/being crippled early if you get unlucky? Do the risks involved outweigh the benefits of doubling/tripling up early? How strong do you need to be to call an all-in early? If hes drawing to 6 or fewer outs? 5? 4? etc... What if hes pushing a flush or OESD at you?

Does you answer change if its a MTT, STT or a 1 table?
Does your answer change if you figure to outclass your opponents?
Do pot odds factor into these spots when you flop to a monster?
Does anyone fold in those spots or is that just bad poker?

How strong - in terms of winning % or outs to avoid do you need to be?

I've seen math done on 2+2 w/hourly ROI calculations to decide these things. I guess I'm looking more for a practical philosophy discussion than that.

Thoughts?