New to me Interarms Parabellum

[DonVoigt]

Lugers like oil, any good gun oil- thin not thick, no grease.

I'd clean and lube after each shooting session.

One of our members shoots his luger in competition, he will come along and give advice on a "lot" of shooting.

I doubt any of the rest of us would fire a luger 5000 rounds; I wouldn't- I have 6 I call shooters and the most any get shot is with one or two full 32 round drums in a session.

Springs should not require changing until you notice a change in ejection pattern or distance, again JMO. There are only 3 coil springs that do work, ejector, striker, mainspring.
The ejector is a flat spring and subject to fail as any leaf spring will - or not. Leaf springs on the mag catch and the sear bar not likely to fail. forgot the very small spring in the disconnector, they don't "fail" but may get stuck due to dirt/dried lube, just keep it lubricated.

Mags- just use them, they will be "stronger" than you are used to.

Maybe this will help, just remember the Luger was a military issue firearm for 60 years, so it is a robust system; being replaced for reasons of cost rather than performance, IMO.