I upgraded mine at about 5000 rounds -- which, generally speaking, is when most recoil springs (which, I think, is what you're referring to) should be replaced.
It was time to replace mine, so I went with a higher poundage (16) Wolfe spring.
THere's no real advantage to upgrading unless you're shooting a lot of hot loads. (I don't shoot hot loads, and may switch back to a lower rated spring the next time.) The 16 pound spring makes it a LOT HARDER to rack the slide.
