Most folks don't realize that crimp connectors using copper wire need to be what is called gas tight. If not then the moisture always present in the atmosphere will react with the copper and dissimilar metal of the crimp connector and will sooner or later fail. A good example are the clamp on the wire battery terminals. I repair lots of trailer wiring. Most new trailers have crap splices and ground connections. Guy brought me a truck where the dealer installed hitch and wiring. Less than 2 years and the scotchlock style connectors and black tape failed. Imagine that. Then you have the wire nut and black tape crowd.