As to your generator question, . . . I assume it's a diesel, in which case 5000 hours may or may not be a negative. As opposed to a vehicle engine, . . .the gen set runs at a constant speed (1800 RPM) which is a positive, the elect load varies which will work the unit harder if heavily loaded however, . . .this is good (to a point).
Light loads are harder on generators as the engine never works enough to burn carbon build-up out of the combustion chambers.
If the unit was maintained (timely) with oil & filter changes not abused, etc, . . .5000 hours would probably equal something around mid-life.
At one time I worked for Thermo King (trailer referig units), . . .they used 4 cyl Mercedes & Izusu diesels to power the AC compressors (that ran at a constant 1800 RPM) and both engine applications would easily clock 15,000 hours before they were ready for a rebuild. (provided they had somewhat regular maintainance)
I would suggest that you check into the maintainance history & usage on the generator, . . .this would give you a better feel for it's continued longlivity.