It may be hard decision for some to decide if they want to reline a pool or if to remove the pool. It all depends on what your lifestyle is. If the pool is still otherwise in good shape and is being used, then it may make sense to replace the lining in a pool. But if it looks like it may need quite a bit of repairs, no one is using it, and the up keep is just too much then it may not make sense to keep it any longer. The cost of replacing a liner runs anywhere from $3500-6000 on average, just for the liner and installation. This due to the size and shape of the pool. This does not include the other upkeep costs that are involved in owning a pool.
Pool removal is on average $8000-10,000. Many factors that go into that cost are the size of the pool, access to the pool and anything that needs to be moved and then replaced. At the end you get a backyard as if there was nothing ever there. Pool removal need to be done properly or you will have a swamp. To avoid this, the concrete need to be broken up in the bottom, liners and metal removed and then clean fill (a lot of it) placed in the whole. From there its up to you what you want to do with the space (garden, grass etc.).
In the end, deciding between fixing a pool or removing a pool all depends on the amount of fixing it needs and the lifestyle of the family.