When you mean pull them back too far, are you talking about squeezing the handle all the way? Because I had an issue with that, but it wasn't the brakes, it was just the handle being loose. Just needed to tighten the screw and fixed that issue.
Anyway you can describe "mushy" a little better?
Even better, any idea of a mileage threshold where the brakes may just start to go? 1500, 2000, 3000 miles ridden? It could be all relative also to how you ride and if you always come to hard stops or apply the brakes gently. But I'm guessing that after a certain amount of miles ridden, you probably used your brakes enough that they probably would need some sort of servicing regardless.