A small explanation. The newer method Sony has seemed to use to totally eliminate broken triggers and even squeaky triggers is to simply place the spring (1) onto a hinge totally separate from the pivot (2). In launch models and somewhat later, the spring was always placed onto the pivot (2) which caused squeaking and ultimately, a broken pivot since the stress and wear of having that spring constantly moving onto it caused it to break easily. Now this problem is potentially eliminated on both fronts due to no stress caused by the spring on the pivot. Awesome job Sony!
More at (including images and more) :
http://gearnuke.com/sony-fixed-dualshock-4-trigger-issues-improving-build-quality/