On the cost side, for a northern pool (where you drain x% of your pool each fall) and for locations that receive a lot of rain which overflows the pool, there is the cost to replenish borates as well.
I had added them years ago to assist with pH buffering, which worked as expected (add more MA less often), but come spring I had to add more borates to get the level back up and I didn't want to continue with that expense. And since my pH stabilized to a large degree over time, there was no longer a need for them in my case.
If my water was any more sparkly than it is today, I'd have to wear two pairs of sunglasses, so that would be another expense as well.