I've been watching a lot of the videos on the site, the great hands section mainly, and it keeps coming up that raising 3x is 'old school' and not done a lot anymore...

Pretty much every raise I make pre flop is 3x so I'm now wondering, if it's bad or old school play, what should I do instead? Is 2.5x better? Or 4x..? 

I often see players on tv shows raising by what I think are really odd amounts. I just can't figure out how they reached the conclusion that the amount they are raising by is suitable or correct or whatever. It's the same for some people I play against online; it's as if they have just mashed their keypad and pressed raise. 3x just seems ike a nice amount to me, plus I figure that if you consistently raise by this amount (or any amount I guess) it would be more difficult to pick up on potential bluffs, on the button for example.

Anyway, it'd be great to hear some people's views on this to see where everyone stands.

Thanks for reading.