When I had my G17, years ago, I left the mags loaded and over time, they developed cracks between the witness holes and were pretty damned useless afterwards. These were the old school U-notch mags. Im getting a gen 3 model 23 hopefully tomorrow - the guy is giving me 5 13 round mags as well as 2 10 rounders. All metal lined and drop free -- this makes a difference, right? I mean, I like having a fully loaded weapon at my disposal and dont like to think a lot of rotating mags - unless I really have to.