For me it was more a case of starting out with a crappy cheap controller and just natural wear and tear of my next controller's R1 and L1 buttons. The R1 in particular lost its seating and would sometimes just fail in the midst of battle. Since getting a better 3rd controller, an F710, I haven't had any issues since.
On a slightly related note, DS/Bloodborne is the only game I can think of that can raise my heart rate to similar levels of doing vigorous exercise. It's interesting as I often get a similar feeling after lifting weights. Can't say it's as beneficial to one's health as actual exercise but interesting nevertheless.