An interesting thought on the spray-in bedliner. I have no experience with them either but have been told that the problem with spray-ins is that, if the material is breached, moisture and dirt can get between the steel and the liner and begin to break down the metal and the rest of the bond with the liner.
I just can't bring myself to be concerned wih loosing paint on the working surfaces of implements and tools. The hood and fenders...well, that's a different story. Even then, it's a tractor, not a car. Having grown up working on ag farms and later on state and private tree farms, we always thought a tool that still had its paint on it afer a month was a waste of money. Everthing else from a spade to dozer blade that would be exposed to the elements got cleaned and wiped wih an oily rag through the season, then washed and quickly coated with cheap paint when it was put up for the year. That paint rarely lasted a month after the next season started.
At my level of use with my loader, I can't imagine ever having a bucket deteriorate from rust due to my non-commercial use. I also store it in a shed. As was suggested, buy a can of paint every fall; wash it, wire brush it if its bad, then spray a quick coat on the bare metal.