Do you have a Sig?
What gun/s do you have?
Replacing springs depends on what you have.
General overhaul or high round maintenance of a semi-auto (depending on the gun)
Recoil spring/s
Ejector spring
Ejector (maybe not)
Firing pin spring
Firing pin (maybe not)
Recoil spring guide (if its plastic)
Magazine/s (or springs etc depending on the gun)
You can add to or take away from this list and without knowing the gun/s, they can't help
Something else, if they don't need replaced, it can get expensive just buying parts for a gun.....waiting on input