one of mine has over 50k shot (g17 GEN2).i needed to change the striker spring,and the striker itself because the end that goes into the primer broke.otherwise,apart from an internal spring kit,there's not much that can break on a glock.it's more about extreme wear and tear after tens of thousands of rounds. however,all my glocks gets the full lenght stainless steel GR mod .i don't like the plastic GR idea on any gun,while it's probably for peace of mind (since i don't like the idea of a plastic GR haha).