This is a tough question since it really depends on alot of things. How is the table? Who is in the blinds? How big is my stack? How big are the blinds stack?

In generally, I tend to steal blinds when I feel that the chip I get by having everyone folding brings something to my stack. Let's not say I have 5000 and the blinds is 15/30. I could care less about blind stealing then. But let's say My stack is 1500 blinds is 50/100. I find myself in MP2 with 75 of hearts for example. I gladly raise here if its folded to me being happy if I take the blinds. If I get called, I will get payed off bigtime if I hit my hand but if I miss entirely and feel that my opponent may have hit I will give it up. There are too good sides with this as I see it, I can steal the pot after the flop if I have a good feeling, or I can flop a well hiding monster.

So in short, it all depends between my stack, the chip stacks of the players left to act, my hand (it does matter to some point, yes) and who is in the blinds. If it's a really tight player and he calls, I better be careful post-flop since he got something. You get the point, it depends...