My pool is now in its 9th year, close to the liner lifetime. I have a couple of symptoms for your consideration:
1. "Squishy spots" in the deep end, on the angled portion just below the straight wall. You can feel them now for the last year or so.
They do not appear to be growing, are they pinhole leaks? Don't sweat it until the water level starts dropping?
2. Faded areas. One pool guy told me that my extremely low calcium hardness was leaching the color out of the liner. Some parts of the print are perfect, others nearly bleached white. I thought that the liner vinyl was chemically inert, and that was not really possible, but he sold me some calcium-up, to produce I think 75ppm of hardness, as a minimum level. Actual name on the tub is "EZ Clor Calcium Elevator".
Is the true test just whether or not you can keep water in the pool?