Calling bullshit on this one. I have one, it's positively wonderful, but the filters are expensive and per the manufacturer's recommendation you're supposed to change them all simultaneously. So when one times out, they all time out. This runs approximately $150 a year minimum depending on usage.
$150 per YEAR at american prices is approximately nothing. That's a measly 41 cents a day.
People spend far far more than that on far far more frivolous things without thinking twice.
Not that I don't love and respect Wirecutter (I don't), but I'm on team "I like how my water tastes when it's filtered."
Some units give you different fixed timespans for each. For that reason, I just use the Reverse Osmosis stage and ignore the rest. RO is the last step, and in theory it renders pure water meaning the only reason to have the previous ones is to pre-filter somewhat the water and extend the RO cartridge lifespan. Problem with that is, first, there's no way to gauge when each filter is spent. Second, they're priced the same anyway, so why even bother. Just go straight from tap to RO! Keep the post re-mineralization stage if you want.
"post re-mineralization stage" is actually "ph adjustment".
RO makes water more acidic. if water was somewhat acidic to start with, it can get more acidic or become corrosive.
RO doesn't output pure water. if you want pure water you slap DI filter after RO membrane.
Ph change is one part of the result, not the goal. The goal is water purification.
those for example https://www.freshwatersystems.com/collections/specialty-cart...
or those https://www.freshwatersystems.com/collections/filters-media?...
RO membrane doesn't remove chlorine iirc or vocs. On the other side chlorine degrades membrane. "nominally clean tap water" can have enough dirt to clog membrane if you don't auto backflush it frequently
But let's assume it costs you $150 a year. Thats less than $0.50 a day for drinking and cooking water. I doubt you could buy any significant amount of bottled water for fifty cents.