We're still regretting a bad decision from three years ago.
We got rid of a wonderfully comfortable, deep, and incredibly heavy 1930's bathtub because it had a scratch. It went to a salvage yard, so it didn't go to waste.
But we wish we had it refinished instead.
There are lots of companies that do this; most are small and local. To get a bright and shiny new finish, they use an epoxy polymer, meaning 1) the process doesn't smell good and 2) the finish is not as durable as the original porcelain enamel, which is baked on in a factory.
To us, any toxic offgassing is offset by the savings in energy and materials of not making another bathtub. And the comfort of an old, heavy, and heat-retaining tub... that you can't buy at any price. Refinishing runs around $200 in our neck of the woods, or a shade less than we paid for our new, shallow tub. If you've had it done, what did it cost you? Would you do it again?
image by jynmeyer via sxc.hu