I think it depends on what type of camping you do and your physical abilities. We use our tow bar about every third trip and we're not full timers, so I take mine off and store it in the garage. I think it's better for the tow bar to keep it out of the elements.
Physical ability is also a big issue. The tow bars are heavy and can be awkward to lift and install in the receiver. I cut down a cheap Harbor Freight dolly and made it into a dolly for the tow bar. Everything stores on the dolly and I roll it into my garage.
