New to water filter systems.
I don’t know enough to make a good decision.

Getting bc my son has eczema and it’s getting worse, and want to stop buying filters for fridge, and the added benefits of better skin and hair, and better pipes, less cleaning due to mildew/etc, and less money on soaps & detergents.

Kinetico through Costco offered the double tank & R/O under the sink for about $5900

EHS saying the salt filter is not needed, neither is the water softener. That we should just be fine with the de-chlorinator and R/O under the sink. For about $2000.

I’m in Ajax, Ontario. Using our wonderful Lake Ontario water. (I know it’s better than many other waters but still not the best)

Thoughts on how long these systems will last?
Why I should have one over the other?
Why it may be better to have two tanks or one, if so?
Warranty of one over the other?