Does it crack?
Is this typically under warranty with pool builders?
Does it need to be replaced? If so, how often and how much does it cost?
After a period of time you may see some small cracks.
I've never had to provide warranty for this product. But, I would warrant for 1 year.
It will last for many years. Initial cost to install will vary between $4-7 per foot.
For residential applications I usually dust the top of the mastic with sand to add a little texture.
We had a minimal amount because it was only needed on 2 sides of the pool. You could run into a trip minimum. We paid on the higher end because of that, but the hours of not having to pull weeds from that crack times years is well worth it.
You could do it yourself...
I found this DIY product on google.