It depends on the weight of the spring. The “standard” 16 pounder is pretty much done after 1,000 rounds of 230 grain hardball. 18 and 20 pounders can go longer. I generally changed out the heavier springs every 3,000.
The last time I was at Glock I believe that they said change the recoil spring assy. at 5K. I don’t remember there being numbers for the other stuff.
For all the Gen4 recoil assemblies?
The ‘‘01’’ assembly (first time I had a Gen4) is what I was referring to.
I’m not 100% sure the numbers would change based on weight of spring.