Kayzap- don't believe the hype. I recently called Colt about this very same subject. I was told that in a Defender/New Agent it was 5000 rounds...and furthermore that a 45 version would require springs sooner than its 9mm counterpart.
Until the ghost of Sam Colt or an actual Colt engineer tells me different, I'm shooting until I start to notice FTE, FTRTB or stovepipes and then contact the company for a new spring set.
I bought a used SVI .40 S&W pistol (high cap/polymer frame semi-auto) about ten years ago. I've shot many thousands of rounds of major caliber ammo through it and never changed ANY springs. The only problem I ever had was a broken extractor about seven years ago. I put a new one in and it's humming right along.
I think the advocates of frequent spring changes are the spring makers!
Seems that life of springs is a question of eternal life itself. I have worked on guns hundreds years old that still had good spring when the rest of the gun was wore out. Springs in other things last almost forever, like valve springs in automobile engines, flexed couple thousand times per mile and last well over 100k miles. Chassis springs same situation. It would seem a gun spring properly designed and manufactured of best alloy steel, tempered, etc should last as long as the rest of the gun. I obviously don't have any answers but would really appreciate some convincing information.
I've shot 1903's that haven't had a spring change in over 100 years. Its amazing what those old Colts can still do.
The only reason I would purchase another spring set would be to get one before prices go up. If history is a guide, my great grandchild may have to complete the spring service sometime around 2100 AD !
I agree with some of the others.
I don't buy the HYPE to change out the recoil spring at specific intervals,like oil changes...........I use F.L guide rods, as I like them but I won't say they contribute anything to spring life, 'cause I can't prove it.......... But I don't change springs w/o a good reason.
I think the only reason the question gets answered with a specifics, is because the questioner "wants" an answer, and giving a "specific change point" makes the answerer feel superior, or it amounts to a sale for him.
My 1918 appears to have original springs still in it. Well, I am assuming it does since everything else on the gun is original. The springs are a bit soft, the hammer spring is actually loose at the top of the stoke. For something that is about 100 years old I can't really complain. Just keep that in mind before you start swapping springs.
My feeling is I used to change springs like I changed the oil on my truck. Now, I tend to shoot until either I have a spring related failure to feed or eject. Springs last a lot longer than you would think.