First time Glock owner, or soon to be. I'm set on the G34 or 17L. Wondering...if I were to buy a spare parts set for the future, where and what exactly would you experienced Glock owners suggest I buy? My understanding is that these guns just go and go and go. So I realize that with any luck it will be a long time until new parts are needed. But just the same, what should I expect to buy?