Wilson 8-round magazines seem to use "less powerful" springs than some other 1911 magazines. Of course, some differences are required in order to accomodate an extra round, too, regarding both the spring and the follower. I've had them start exhibiting signs of spring weakening after fewer rounds fired than some other brands, or 7-round magazines in general.
When the FBI was using them in their single column .45 pistols, it was reported that they'd decided that their magazine springs would be replaced on a rounds-fired usage, and/or a time-left-loaded criteria. If I remember right, it was reported the criteria used was after 2,500 rounds were fired, and/or they'd been left loaded for 6 months, whichever occurred first.
I know some other folks who carry cocked & locked 1911's for work, and some of them have reported similar experiences where the magazine springs in their 8-round Wilson magazines started either failing to lock the slide open when the magazine was empty, or the last round apparently wasn't being lifted upward fast & firmly enough to be properly stripped, fed and chambered. The last guy that was talking to me about this told me his magazine started exhibiting apparent spring-related issues after he'd only fired 1200 rounds. Replacing the springs resolved his problem. Of course, he's also required to carry W-W RA45TP, which is a 230gr +P load, and that can add the extra consideration of introducing some slightly increased slide velocity, too.
I prefer 7-round magazines for Colt style 1911 pistols, and find the S&W TDA and the SIGARMS P220 to be fine with the supplied factory magazines.
Personally, I no longer buy Wilson magazines. There are a lot of other quality magazines being offered for sale nowadays.
Magazine springs, and their durability and long-term functioning, are often a popular subject of some debate. Some folks aren't even satisfied when the spring makers, or engineers familiar with related metallurgical issues speak out, either. ... "Uncle Charlie's WW-WUN 1911 magazine was left loaded since Moses parted the waters (pick the legendary Moses of your choice
), and it functioned just fine when he needed it that one time. 'Nuff said" ...
Or something along those lines. But would you
want to go into Harm's Way with a magazine spring that old????
Seriously, I've decided to make it simple for my own needs and purposes.
In my last S&W armorer's recert classes, we were told that S&W has decided to recommend to their L/E armorers that magazine and recoil springs be replaced every 5,000 rounds and/or every 5 years, whichever occurs first. Sure, they've gone longer and functioned fine ... but in this age of liability, better safe than sorry, right?
In my last Colt Rifle armorer's class we were told to leave the rifle magazines downloaded by 2-rounds if the magazines were going to be stored long-term with the rifles in a vehicle. We were told this would help preserve proper spring strength toward when we might really need it. I don't remember that we were given any specific replacement recommendations, however. Maybe that will have changed when I attend my next Colt recert class. Who knows?
In my Glock armorer's class we were told that we should replace them when they started to exhibit any signs of obvious weakening. We were also told to leave them sit empty for the time it took to detail strip and inspect the pistols annually. One requested opinion was offered that 8 years was too long to go without replacing the magazine springs, because someone asked about that specific time period. I know a L/E Glock armorer who told me he that he had had to start replacing the magazine springs in his agency's G21's annually, because he saw too many apparent magazine spring-related malfunctions during qualifications ... and after he started replacing the magazine springs annually, the malfunctions stopped. No +P ammunition was being used, either, if that means anything.
I was told in a non-factory 870 armorer's class to unload the shotgun magazines once or twice a year, at least annually, and let them sit empty for the time it took to inspect the shotgun. I was also told that the instructor's previous agency (unnamed, large fed agency) had experienced that the extended magazine tube springs had generally seemed to weaken faster than the shorter 4-round, standard magazine tube springs.
Bottom line? I think everyone should carefully research this subject for themselves ... read their owner's manuals, check with the manufacturers of aftermarket magazines, listen to folks with first hand experience in this subject that seems non-biased and uninfluenced by urban legendry, pay attention when they attend various recreational shooting functions and competition venues, etc., etc. ... and then make the best informed decision that suits their needs, and makes them feel comfortable.
I've decided to replace my magazine springs on some reasonable usage (shooting) and/or time criteria ... or whenever I discover some sign of developing weakness. Hey, sometimes a spring may just become weakened and fail. They're just parts. We expect a lot from springs. It's not all that expensive to replace them, though, and is probably one of the less costly types of "insurance" we can buy ...
Just my 2 cent's worth ... I'm certainly nobody's expert anything ... and I don't begrudge everyone else their money's worth of opinion, either.