The concept of having interchangeable, standardized parts is actually kind of a new idea from the Industrial Revolution. Before then, everything was custom-made to fit. The example that comes to mind is firearms. All of the muskets and rifles used in the revolutionary war, for example, were hand-made and hand-fitted. The lock from one rifle wouldn’t necessarily fit on another. If your stock broke, you couldn’t just go get a new stock and slap it on - you had to bust out the woodworking tools and make a new one.
I’ve heard of a diesel-electric logging truck that uses this concept as well. Use the batteries going up the mountain empty, charge them again going downhill loaded.