The trigger on my Circa 1996 (box stock, except for sights) Glock 26 that I've carried since I bought it is becoming harder to press – living near the coast in the humid South means that this little gun has been sweated on quite a bit (inside the waistband), but I've kept the gun clean and lubed throughout it's life. There are no visible signs of oxidation inside or out.
I haven't kept a round count for it, but I would guesstimate more than 4,000 rounds, but less than 8,000 rounds. Dry fire practice would have trigger presses that are orders of magnitude greater than this.
Is there a short list of parts that I should consider replacing to clean this trigger up (or just as good preventative maintenance)?