I personally would only use polish to remove hazing or oxidation or scratches. What could be done (for example) is once you've thoroughly washed your car give the paintwork a polish then give the car another quick wash to remove any polish residue. Then you would apply a wax coating to protect the paintwork.
I apply wax nearly every other time I wash the car (so about every 3 or 4 week intervals it gets applied). However, most directions for wax products state that you can leave it until water no longer forms "droplets" on the bodywork. (Wax forms a sort of clear 'film' on the surface of the paint, water does not adhere to this film and so forms droplets rather than puddling together. Any good waxed car after a rain storm will be left covered in little droplets of water which will simple roll off the surface, in a strong breeze for example).
Hope that helps
