This hot tub is over 40 years old. The original equipment failed decades ago, the plumbing has disintegrated and the cabinet has rotted away, but the acrylic looks pretty much exactly as it did straight from the factory.
Never judge the condition of a hot tub by how good the shell looks. People wanting to sell us their hot tub often say, “the shell’s in great condition”, but that means nothing. Shells that are decades old can still look good. Nobody knows how long shells last because modern hot tubs have only been around since the 1970s. I joke that in 20 thousand years from now, aliens will find these perfect-looking shells when they do archeological excavations on our planet, and wonder what the heck. It’s everything else (frame/cabinet, plastics/plumbing, pumps/electronics) that will break and come apart over time. We’ve cut up and scrapped hundreds of beautiful-looking shells because the rest of the hot tub was too far gone to attempt refurbishing.