I'd say that there is no set life span. Every pool is different, if you think about it. The quality of the workmanship when made, the quality of the water care during its life. My 1958 pool was fine until my father got old and lazy and just lost interest in taking care of things maybe 10-12 years ago. Today the plaster is deeply pocked all over. But it doesn't leak, so it's just cosmetic........for now.