John Farnam has a quip about carrying spare magazines in pants pockets.

Last weekend, a student did just that, and, during a tactical drill involving movement, he was unable to complete a reload, despite repeated, enthusiastic attempts! The new magazine (when he, at long-last, finally fished it out of his pocket) refused to lock into place within the pistol.

A close examination revealed the issue: A single dime, that had been sharing the same pocket occupied by the spare magazine, had wedged itself between the top round and the feed-lips. How it found its way into that exact spot is a continuing source of mystery, but it somehow managed, and the anguished result was a magazine that adamantly refused to fully insert!

John’s conclusion is sound….

Don’t carry spare magazines in pockets, rattling around in the bottom of handbags, nor other inappropriate places, where coins, paper-clips, lint, and other objects that may be sharing the same place will find their way into the magazine in such a way as to make a hash of your next attempt at a rapid reload!

…. but I’m not sure I’d go so far as to say not to carry one in your pocket, period.

I will say the realities of pocket carry are true, thus you must carry accordingly. I would not carry a mag loose in my pocket. Instead, use a mag pouch made for pocket carry, like the DeSantis Mag-Packer. This protects the open end of the magazine, plus it holds the magazine in a known and stable position for a reliable draw. Furthermore, it breaks up the outline of the magazine in your pocket to aid in concealment.

The other part of the equation is your pocket must be dedicated to carrying the magazine (in its pouch). If you have anything else in the pocket, like coins, they can still find their way into things… and Murphy’s Law will be with you when you least need it. If you don’t have enough pockets to carry all your stuff, you’ll have to come up with another solution: more pockets (e.g. cargo shorts), carrying on your belt instead of the pocket, or even foregoing a reload (tho I’d consider this only as a last resort). I’m sure you can get creative with alternative methods, but be sure you practice with that method and work to find the faults and problems and debug the solution before your life depends upon it.