Originally Posted by H&K 4 LIFE
Maintenance- same as a Glock. Doesn't need heavy lubrication or grease to function properly.
Parts replacements- Most likely unnecessary. The recoil spring is rated for a 20,000+ rounds service life and I have seen many USP's/USPc's go much longer round counts with zero parts replacements. If it doesn't look heavily used then chances are it is no where near the point of needing anything replaced.
I would buy a spare LEM TRS (trigger return spring) just to have one handy.
Night sights- I am fine with the Meprolight Tru-Dots that HK uses as their factory night sight option.
The USP guns are tanks.
99.98% sure all you need is a light lube and ammo.
If you decide to swap the TRS there are several LEM configuration
available adjusting the trigger pull you may want to look into.
All five of my H&K LEM guns have been converted to Light LEM
using factory springs.
Check the HKPro website for information.