I stopped using shampoo nearly 10 months ago and my hair is almost to the point where I really want it. Quick and easy to take care of, just a rinse with water while rubbing my fingers on my scalp, then some brushing and I'm done with it. I'm currently using baking soda and apple cider vinegar once every 4-5 weeks maybe, then water the rest of the time. I think I might be stuck at this frequency if I keep using our really hard water in my hair every day.
The transition has been long but having a public facing job I didn't want to go a single day with bad or greasy hair. I completely replaced shampoo with about a teaspoon of baking soda and a tablespoon of vinegar every day. I wet the baking soda with a couple drops of water and rubbed it in my dry hair. Then diluted the vinegar in probably close to a liter of water and rinsed it out. I didn't see a difference in this vs shampoo and neither did my wife.
I did that 5 times a week then just water on the weekend. After a couple weeks of this my hair on Saturday started looking pretty good, but was still kind of rough on Sunday. So I went to every other day and it worked out great. A couple weeks later I was able to go 2 days, then 3 and so on till now where I'm basically at once a month. I was fine with this rate of progression as I never once had to hide greasy hair, it always looked fairly good. The feel of it took much longer to get silky smooth as it is now. For severl months it felt...more like an animals fur perhaps, firmer.
It's all good now and I'm much happier. It's quick and easy to deal with. I did have to switch to a boar hair brush from plastic and I think that helped out a great deal. Brushing it while it dries I can see and feel my hair fluffing up. I don't think I could ever go back.