We had reglazed the tub in our last house and had the non-skid applied and it was hard to keep clean. We had THIS house on the market and decided that the pink bathroom might be the reason we were not selling, so we had the bathtub reglazed and opted to NOT have the non-skid coating, because the tub (which is only used for guests) would then look pristine. We have since taken the house off the market and now the slippery surface is a safety concern. But we DO plan on putting the house back on the market, so we don't want to stick appliques to the new tub. The non-stick coatings suggested (slip doctor) say that they work on porcelain, but I wonder if they will stick to the epoxy finish. I guess the only way to know is to try.

After slipping on a plastic mat with suction cups that didn't grip the tub, I bought non-slip shower treads on Amazon. They're made by a company called SlipX Solutions. Several posters on GW recommended them. They're fabulous: clear, not too visible, clean easily, and best of all provide excellent traction. I highly recommend them.

About 8 months ago I removed what I believe is exactly as you've described: a metal framed sliding glass door from a cast iron bath tub with tile up the walls. (I then promptly destroyed the tile and tub, but that's irrelevant to this discussion...) There had been some holes drilled in the wall tiles, but the tub itself seemed to be fully intact. There was a lot of caulk everywhere that would need to be scraped off and then cleaned up with some sort of chemical. (I found a caulk remover from one of the big box stores that was fairly cheap, easy to use, and didn't do any damage to any acrylic tub so certainly cast iron and tile could handle it.) I'm guessing you also may end up with some holes in your tile where the door is secured that you may need to patch and/or cover with the new door.

We will probably reglaze our tub when we retile, but I would hesitate to reglaze a tub in a rental property unless the renters could be trusted to take to heart my very specific instructions on how to clean it. Several of my co-workers have reglazed tubs. After 8 years of good performance with Eva's first reglazing, she is now in year 5 of a second reglazing. Carol, however, reported failure of her tub surface after only 2 years. When we asked how she cleaned it, she listed Magic Eraser, scrubby sponge, Tilex, and whatever soap scum buster she had on hand. Either her reglazers did not leave cleaning instructions for the tub, or Carol did not read them. A reglazed surface is easily damaged by anything abrasive, and it can crack if something heavy or sharp is dropped on it (e.g., a hand-held shower head, a tile-scrubbing appliance). To optimize the longevity of the surface, the cleaning instructions I've seen recommend only a soft sponge and a gentle soap scum dissolver. Period. Not sure it's realistic to trust a renter to use only those items for cleaning the tub.