stealing the blinds

Does going steling the blinds make a big difference?

Stealing the blinds gets moe tempting as the tourney goes deeper. What criteria do you use?

What position?
What kind of player does the blind need to be?
What kind of cards do you need?
What about stack size?
What kind of raise do you make?
If you get caught do you back off then?
If you get re-raised do you ever call?
If you call then what do you do on the flop?