Never changed one for wear. I've had one particular Glock 19 since they came out back in the 80s. Spring still functions perfectly. It's got to have 20K rounds down the barrel. I've bought no less than 15- 1000 round cases of ammo and dozens of 50 Rd boxes for that pistol when I shot it annually at the Michigan police pistol matches for probably 20-25 years during my career. I do change my 10mm springs depending on which ammo I'm using. Heavy 220/230 grain 1200 fps loads, I use a heavy spring. Lighter 135-155, I use a light spring. 155-180s, the factory spring is out back in the gun.