I know exactly what this poster is talking about. The R2 button no longer has any Resistance and it permantly depressed. Playing MGS4 my weapon kept changing and I wasn't even touching it. Like the spring that pushes back on the button is worn out. The L2 works fine and my Sixaxis from 2007 works fine though.
I blame Socom. It easily has had the most play time out of any game I own and to sprint you have to hold down R2. I'm guessing swapping the sprint between R2 and L2 before this happended would of been a good idea to get a more even wear on the triggers.

my DS2 L1/L2 buttons always used to get stuck. but i havent had a single problem with my controllers in the 6 months ive had my ps3.

I don't know. Mines work just fine. Maybe your a little too rough eh!

i got a dual shock 1 since psx days and still works great

Actually, so does mine. It was my dual shock 2 and sixaxis controlers that kept screwing up.

As does mine... from 1998 I think. It's the best built of all, it's an unbreakable tank.

Mine's were a bit loose back when i was playing Burnout Everyday. They've stiffened up a bit now though.

i dont like the PS3 controller i think the 360 one is better.

I have the same problem on my 360 controllers. The analogs get loose...

I haven't played a Ps3 enough to know if they get loose.

Try these:

http://www.amazon.com/gp/product/B001IAOEXU

I've been using them for a while and they really reduce how much you have to press the L2/R2 buttons.