I do the baking soda + apple cider vinegar thing, though the water in my area is so hard and mineral-filled I often find myself alternating between baking soda and a solid shampoo to get properly clean. I'd wager I wash my hair every 3 days, more often if it's insufferably hot outside, but a quick water wash does the trick in a pinch.

I made the switch to BS and ACV mostly due to thriftiness and convenience, to tell the truth! Keep in mind that my hair has always been relatively easy to care for (wavy/curly mix) and I barely noticed the transition- the combination simply doesn't work out for some people. I didn't go cold-turkey on the hair products, either- I've heard grease-bomb stories from others who tried to go directly to BS and ACV.

I do an egg mask on my hair once a month too- it feels strangely delightful and soft afterward. Cx