along with the spring, the detent wheel, which is plastic, can wear and cause fuzzy shifting or even slipping (upshifting).

parts are available and there are people who can do this repair, not expensive. Do it now before you assemble your new bike.

Bradford Bikes can do this. There's a video on youtube that shows how to disassemble / re-assemble, but that doesn't solve the replacement parts problem.

and store your bike with the chain on the small cog (r) and small ring (f). that will keep the springs from taking a set

/markp