Actually, the recoil spring in the .40 weapons should be replaced every 3500-5000rnds, this coming from the Glock armorers course I took back when I was in LE and out dept issued the 22/23. The Glock 23 I was issued had logged over 12000rnds and regular spring replacements every 4k. I've also handled high-mileage 23's that had NO springs replaced and there was a noticeable difference afterwards. I'd also say replace the trigger spring as I've seen them break before with higher round counts. I've never seen an extractor fail though. Another part to watch pending the manufacture year of your 23 is the takedown lever spring, some were very thin and could break after alot of use, sending the slide downrange. I've seen that happen twice with Glock 22's after thousands of rounds. It's an easy fix though if the springs are on hand. I keep all the little parts around just in case. Aside from that, we detail cleaned our Glocks once a year regardless of round count. Probably a good idea pending the conditions your sidearm is exposed to. Also check the striker tip for any signs of deformation, and you could replace the striker spring as well just to be safe. With maintenance like that, the Glock 23 will last a LONG time. I follow the same routine with my 9mm Glocks as well just to be safe. The recoil spring is by no means designed to last for the life of the weapon, there is a point when it loses strength and the weapon starts getting battered, especially with hotter .40 loads.
