We have a nearly 30-year-old fiberglass garden tub in our master bath. The problem with these old fiberglass tubs is that they tend to develop hairline cracks with age. Our did just that, and was drip, drip, dripping down into the kitchen.
So we went with a service that patched the crack, and reglazed the whole tube, enhancing the appearance, and supposedly reinforcing the aging fiberglass.
Cost was under 600 bucks. Looks great. Time will tell how well it holds up, but I've done do-it-yourself patches on fiberglass tubs in past that lasted for years. And my skills in this area are far from professional.