I like gen4's but gen 3's and earlier models have cheaper guide rod/recoil spring replacements. 4's cost twice as much as 3's. Still a cheap fix, and not something to worry about often.
10k rounds is pretty good. I have always heard to change them every 5k rounds. I guess that is to be on the safe side.
I agree that the standard round count for replacing the Glock recoil spring for 9mm is around 7,500 rounds.
Back in 2011 when Todd Louis Green was using & abusing a Gen4 Glock 17 for 71,260 rounds, he was replacing his recoil springs in his G17 about every 7,500 bc that's what Glock said was the suggested range for replacement.