Say you have some light rusting and barnacles on your frame. Would the most expedient fix for that be sanding, primer, then finish coat.
That sounds like the fix - but I've never worked with paint before so I'm not sure if there's a extra step or if the rust barnacles indicates a problem that needs a different approach. We're not talking huge areas - maybe patches the size of a quarter at most. Generally at the weld joints where the metal is rough from the weld process itself and where water collects.