Ive got routine for my pistol and ar mags. I number all of them. When I go to the range I used #1 today then #2 the next ect. If one acts up I put a mark on it. Then I start again with #1 and go through them all. If one of the marked ones acts up a second time it goes in the trash and again for a third time with any two time offenders getting trashed. after the third time there used I put them in a box and when ive gone through all of them I spend a day cleaning them. Only exception is I keep one 5 round mag for each caliber for load development and mark them as such and those rarely get cleaned. I know I probably toss mags that could be tweeked or fixed that aren't running right but I can get a magpul ar mag for 10 bucks and ive probably bought close to a 100 of them and have never had a bad one. . Its not worth risking my life on some old metal mag that's getting finiky. Now if you only shoot a mag or two when you go to the range its probably not necessary to clean them after 3 uses unless you dropped them in the dirt. But its peace of mind. I do the same with all my handgun mags. But have to say ive never had to toss a glock or m&p or sig man. About the only junk mags ive ran across for handguns is some generic 1911 mags.