With the above statements, it would be nice to be able to manufacture parts for repair from resouces we find.. Not complete complex units, just spares like washers, gears, seals, and other parts such circuit boards, housings, etc etc. Casting,printing,molding,forming,smelting etc etc with a 'parts maker' facilty (put resouces in one end, choose items from PC, start and wait for finished item other end) Its far fetched (sorta) but for the sim it could be made 'beliveable'.. spare parts could for example require 4 different types of resouce (keeping it simple) and a certian volume before been able to be made.
As we replace parts, how about the items that breakdown (pumps etc) have an over all lifespan?? They can be repaired but each repair takes off a bit of there life span until they are unrepairable (we would have to make all the spare parts to create a new unit, ie 4 new spare parts, which is built on the workbench).. that gives reason for manufacturing and truly be able to survive indefinitally