This is counter-intuitive but I guess there are cases where throwing away the part and replacing with a new one is MORE environmentally friendly that reusing the part—when it involves not-so-nice solvents. I hadn't considered this before.
Maybe. Depends on how environmentally friendly manufacturing, packaging and transporting the new part is. I suspect it’s a win in chemical terms most of the time, but it may not be an overall blowout win.