If you do, which I very highly recommend because RO water genuinely tastes amazing (I don’t like tap water anymore, it’s gross and chemical-ly), especially out of stainless steel or glass drinkware, I encourage you to get one with a pump and a 6 gallon tank if you can find a place for the tank to go.

The pump reduces the wasted water to about 1:1 (non-pumped is about 4:1 wastewater to RO), and unless you really don’t use much water, 6 gallons is the way to go, especially if you have multiple people living there, or might do in the future. You might not need it often, but if you ever have company or get an aquarium or anything you’ll be so glad you have the big tank.

The 3 gallon tank I have is adequate for me alone, and would probably be ok for 2 people, but when I do drain it, which I do when making broths, soups, beer, big ice tea batches, etc. or even just filling jugs to take camping, it takes about 4 hours to refill (dont have pump driven, those might go faster, im not sure)

And if you get one, make sure you clean the tank annually. I did not know for half a decade that bleaching regularly, which is pretty easy to do, is important to prevent bacterial growth. Mmm tasty.

My experience is from the Midwest. I definitely cannot speak for the rest of the country but from what I understand its similar throughout the country.