Supposing that a person wanted to get an old project car - something with a lot of very-rusted on fasteners, is it worth getting an impact wrench? Do impact wrenches work well on removing rusted-on nuts and bolts? What should a person consider when purchasing one?

I own a fairly small air compressor, so I’d be a bit concerned about running it continually, but for helping to loosen up some rusted on bolts, I’m thinking it might be a handy thing to have.