Refinishing your bathtub is a great way to make it look fresh and new. Old fiberglass bathtubs, as resilient and durable as they are, are bound to wear down over time. Usually, the paint finish wears off after several years in certain spots. This isn't a major concern because your fiberglass will remain waterproof even if the finish wears down. However, it can make your bathtub look old and outdated. If your fiberglass does have a serious hole or scratch in it, you can patch it.