I'm sure this was asked before, but I am curious about everyone's opinions on this.

after a long drawn out conflict, it seemed like most bellived it was ok im most cases to leave mags loaded for long periods of time(years). with ar or ak mags i wouldnt worry. if it was a rare mag i wouldnt risk it, i also wouldnt keep cheap 22 mags loaded.

For quite a while. I still have some loaded from more than a decade ago. The swiss/germans make the best mags!

I've heard that it is not a good idea to leave the 30rd Thermold magazines loaded for extended periods (i.e., months/years) as it can deform the feed lips.  However, I have not been able to verify this.  Just to be sure, I keep any "hot" magazines loaded with only 20 rounds loaded, but have plenty of loaded stripper clips available should I need to top these off.

U.S. made Thermolds are perfectly safe to store loaded. I have 3 that were loaded back in mid '99, one was tested at about 8 months w/ no problems. The second was test at about 18 months w/ no problems. I'll test the third mag sometime in the next year or so, maybe.

If you want to load a few and store 'em it might be best to cycle them out every couple of years just for personal comfort though. When it comes to storing mags loaded the Thermolds are at least much more resiliant than the Orlites which are prone to cracking. For extreme long term storage while loaded the USGI mags are the best as they won't swell or crack.

You should store a significant amount (or all) of your ammo on stripper clips and purchase several mag loading tools to store with your mags and for your range bag. Str. clips save you time at the range and make counting your ammo simple.

Honestly, I never keep mine loaded.  Not so much for safety reasons, but whats the point?  I keep my shotgun handy and as we all know, those babies are quick to load anyway...  I wouldnt use my AK, M1A or AR for home defense, so whats the point?  Pistol mags, well... can't help you there...