This question will be answered with a big "it all depends". Your pool's life expectancy can be extended if the water quality is maintained and properly cared for. Homeowners and commercial property owners tend to keep their pools surfaces pristine for longer periods of time than they need. When your plaster starts to peel, flake, crack, or become rough, it's time to resurface.
To repaint a pool, the plaster must be in good shape. Pros suggest that the plaster surface be prepped with a wash of muriatic acid followed by a rinse with TSP (trisodium phosphate) and water. (Note: Exercise extreme caution when using muriatic acid and TSP and always follow manufacturers’ instructions.) Also, the old paint must be compatible with the new paint. For instance, rubberized latex paint won’t adhere to epoxy and vice versa.
Because of its flexibility, and resistance to ground shifting, fiberglass is a popular choice when it comes to resurfacing. Your contractor will fill in, reinforce, and sand any chips or cracks to make it as smooth as possible.