duqnuk said:
Hello everybody!
How often do you raise pre-flop in Cash-games? Do you raise very often in good position with marginal hands?
How much do you raise when FRI (first raise in)? 3bb, 4bb? Do you like to vary your raise size?
I know it's a few questions, feel free to reply to how many you want.

I try to raise preflop close to 99% of times. I use 2.5 BB from any position (if possible, when I’m using cellphone I use 3 BB because it’s faster).
This is because for a 6-MAX game I begin using 15% range from UTG: for my own strategy this means 7.5% of times I’m raising value hands and the other 7.5% of times I’m raising semi-bluffs, hands with a very good potential postlfop, even OOP.
From the BTN I usually open from 30% to 50% range depending on table dynamics/opponents behavior.
This is why I prefer using smaller sizings such as 2.5 BB preflop. I never limp because I believe this gives information for the table: if I limp, I would limp my weakest hands and raise the strongest and my gameplay will be easy to counter play.
Besides, I don’t limp because of the rake we have to pay to see a flop and to try to diminish the variance.
For example, I raise 22-66 and 54s, 65s, 76s, from position (CO or BTN) and utilize a sizing of 2.5 BB . SB folds and a NIT from the Big Blind 3-bets to 10 BB (4 times the size of my raising). I usually fold in situations like this.
Another example, I raise the same range and use the same sizing and now there’s a regular Tight player sitting in the Big Blind and it 3-bets to 7.5 BB (3 times the size of my raising): now; I’m more inclined to call, the price is better and I am quite sure Tight Villain will have some bluffs in his range, not like the polarizing NIT, that will show a lot of AA, AK, AQ, KK, QQ and JJ.
A long time ago when I used to play 100 NLHE my raise preflop was 2.16 BB (or 2.16 x).
I hope this could be useful to you. If you have any questions, please do not hesitate to post.