Taking pictures while doing renovations.
 

I was reading a story about a person the did total renovations on a vintage trailer. He took before and after pictures. This helped him get more $ when he sold it. It is also a good idea to keep receits for all parts. We did this when we did a major renovation on our 1990 HiLo. I guess it was just dumb luck. My thinking was it would be easier for the next person that was faced with major repairs.