I looked into reglazing a tub and decided against it. I have no first hand experience with reglazed porcelain, so it may be fine, but all the providers I could find seemed to be directing their services to apartment owners and motel owners who needed a quick and cheap spruceup. The guarantees were fairly short, and when you look at what they actually do, it is an epoxy, not a true porcelain. Since it was for our house and I didn’t want to do the job again for another 50 years, I got a new cast iron tub.
Tubs are pretty much standard in thir sizes and have been for a long time, so you may be able to find one that will match your tile line. Then you have to break up the old one and get a new one in without messing up the tile. I’d think about filling the old tub with sand bags or something to dull the vibrations from the sledgehammer when you crack up the old tub.
If your tile does get damaged, all is not lost. I had some 1930s tile damaged by the plumbers during our repipe. I was sick about it until I found a tile person who made me exact replacement pieces for the tile, even the tile trim. http://www.fayjonesday.com is her website, though I don’t think it mentions her work doing repair tiles.
Once I had the repair tiles, I carefully removed the broken tiles with a 4″ diamond blade in my angle grinder. Hope that helps.
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