You can hear as many so-called 'answers' as you the number of folks you care to ask ...
When several of the cops in the Glock armorer's course I attended tried to press the instructor for a definitive answer regarding the number of years the recoil springs should remain serviceable, the instructor took great pains to dance around the subject. Finally, as folks started calling out various numbers of years, the instructor stopped the questioning by answering one fellow who had called out 8 years, saying that 8 years was too long to keep using the same reocil spring in a L/E service weapon ...
S&W changed their recommendations to L/E armorers and standardized on recommending a replacement guideline of every 5,000 rounds fired and/or 5 years of service, whichever occurs first (with the exception of the 1911-style pistols).
I've worn recoil & magazine springs to the point of them exhibiting signs of excessive weakening.
I've had to replace weakened extractor springs, sear springs, etc., when weakened spring related functioning issues occurred in weapons for which I'm responsible to help maintain, too.
I know of another agency who started experiencing noticeable functioning issues symptomatic of excessively weakened magazine springs in their M4006 pistols at the 7-year mark, and the problems were immediately resolved when new magazine springs were installed.
I know a cop who carries a personally owned G22 on duty, and his pistols started exhibiting functioning problems which appeared related to weakened recoil & magazine springs after 10 years of use. It wasn't until he experienced functioning issues while trying to shoot an attacking pitbull that he finally realized that he might need to consider replacing his springs, and that weakened spring functioning issues weren't just an inconvenience at the range.
I've had to replace more 1911 recoil & magazine springs than I can remember over the years after they weakened to the point that functioning issues started occurring. I know a bunch of SWAT team folks who started carrying 1911's, and who were very surprised when they discovered that 1911-type recoil & magazine springs had to be replaced more frequently than most other service pistols.
I remember talking about this subject with another agency's Beretta armorer, and hearing his surprise when they experienced a broken barrel locking block, and were told by someone at Beretta USA that they should've been replacing their recoil springs every 2,000 rounds on their 9mm pistols.
Now, at last count I've attended something like a baker's dozen armorer's classes (including recerts), and I've talked to a fair number of folks at different manufacturers ... as well as a couple of spring vendors ... and I've heard all kinds of stories and information.
Added to my personal experiences and observations, I've considered the info gained in armorer's classes and shared by various manufacturers and have decided upon my own preferences for replacing various springs in service/issued and personally owned weapons over the years. I take various factors into consideration (including design, weapon size and caliber) and have arrived at my own preferred preventive maintenance periods for routinely replacing different springs in different weapons, notwithstanding the necessity to replace any spring which may exhibit signs of premature weakening or failure. It happens.
When it comes right down to it, recoil and magazine springs are fairly inexpensive parts ... and inexpensive insurance, when it comes to that ... and when lives may be at risk, I tend to lean toward the philosophy that it's better safe than sorry.
Of course, you have to realize that not all firearms owners actually shoot their firearms very often, or may ever run up a significant round-count because of frequent shooting, training, practice, etc., etc.
It's not uncommon during a CCW class for us to observe what appear to be weakened spring related functioning issues in some folk's pistols, especially when it comes to magazines. Not uncommon to observe that the student's handguns are dirty when they arrive at class, though. I remember one other instructor's startled expression when he learned that some of the dirty guns are still dirty from the previous CCW class ... two years prior.
I sometimes ask CCW class attendees how often they practive with their firearms, especially between renewals, and the most common answer is a blank stare ...
