refinshing a tub

Hi everyone! We will be remodeling our bathroom very soon and are debating about if we should refinish our tub or replace it. Not sure how old it is, but has several rust stains on it and I've tried every chemical known to man to clean it and it still lookes dingy. Also, if we should decide to refinish it, any suggestions on what product to use? I like the tub, it's very deep but just won't come clean! LOL

If you are redoing the tile, it would be a good time to replace the tub.

Rust is not something that gets better. Only worse.