If the liner manufacturer wasn't paying for the installation of the new liner, patching the old one is not a bad way to go.

Most likely any areas that would have separated under the stress of filling the pool with water, would have by now. In fact the seam that gave probably wasn't "sealed" to begin with. So it's a good chance it's clear sailing from here on out.

The benefit being, is that you still get the liner itself (the second replacement one). Store and use if for your first liner replacement. Vinyl and materials in general only get more expensive. If the average life span of a liner is 12-15 years for example, that could calculate into quite a savings.

But if the manufacturer is footing the bill for the installation of the replacement and you want a piece of mind, then by all means have it done.

Here's a tip: If you order the same style liner. and have it installed. Save a few section of the old one, to use as patch material in the future. Vinyl can be used with most of the underwater glues that are contained in patch kits. But the vinyl or material provided in those kits is never very good looking as a patch. If you match the pattern perfectly from a piece of an identical liner, it almost vanishes.