How can you fix the left and right stick on the pro controller?

How can you fix the left and right stick on the pro controller?

I've gone through two pro controllers in 9 months. On the first controller, my left stick stopped working entirely. On the second, my right stick stopped working properly (forcing the camera to either slowly drift downwards or abruptly shift downwards whether you're touching it, in any direction, or not). Both issues make it impossible to play most games with the controller, and Nintendo wants to charge me $40+ to fix just one...