IMO, stealing is heavily dependent on the two players to your immediate left and the overall dynamics of the table. If you have a LAG or a calling station in the SB, BB, or that limped into the pot then a blind steal is probably not a good move.
When I sit down at a table I will usually let it run approximately 2 circuits and try to get some sort of read on the blinds, unless of course I just happen to get a nice hand ~AK-AT or AA-TT.
Once I have my read I will try small steals first raising 2.5 - 3xbb. If it works I keep it up, if they fight back I can easily get away. And if they fight back I will raise up to 4xbb then 5xbb then 6xbb. Basically, I feel it out until I get the right amount.
And some players will say by definition raising 5x or 6xbb on a steal is not profitable because you have to be successful too often, i.e. 6xbb would require 3 steals to turn a profit as 2 steals would technically break even. I tend to disagree, because even a steal that does not result in an automatic fold does not mean you give up the hand. You are still in position and may hit a flop.