A nice thought. Unfortunately for me, when the bloke removed the engine from the Porsche 911 I bought as a glider, he just cut off every wiring harness rather than uncoupling them. So, I'm starting a bit from scratch on figuring out which bits are important. I do have the shop manuals, so that will help...My general rule of thumb is to keep everything until you know you won't need it.
Even short bits of local loom should be kept just so that you have the connectors on the end for reuse if needed.