I did bicarb and apple cider vinegar for a year.....
I had 2 little containers one for bicarb. I would put in a couple tablespoons and then a little bit of water
Other one couple table spoons of vinegar and water
Then hopped in the shower and grabbed them after I washed my body. Really massaged bicarb paste on well left for a minute or 2 then rinsed out rubbing head well (nice feeling head massage)
Then poured vinegar on head and massaged in well. Left for a couple minutes then rinsed.
Came out with hair smelling like vinegar but when my hair dried there was NO vinegar smell at all.
Took a couple weeks for my hair to adjust but in the end only had to wash my hair once a week (I have a friend who can go a month).
My hair felt great but I missed colouring it (and DH asked me to get highlights as he loves how they look).
You cannot do bicarb etc if you colour your hair I believe or at least the time of dying hair has to be washed well with shampoo and conditioner.