So I got to this age when some grey hair start to show up. Do I mind? A bit. It is mainly an aesthetic issue for me. I started to get grey on the sides and from afar it looks as if I am going bold. Not kidding. I did go to local salon to cover those bits and the result was good. However it lasted only few weeks and the whole procedure was very pricey. I began to search for something more affordable and hopefully something more natural like henna. Most of the hair colours were very expensive and and a long list of chemicals in it. Finally I found one henna product in a small Indian shop. I have been using this for 3 months now and I am happy with results. Did not have any adverse reaction to it. To put the colour on is a messy business. You need a pair of disposable gloves, comb and shower cap. I usually put some newspaper down because the bathroom floor can get dirty – henna really sticks and is hard to wash off. I tried Black and Dark brown shade from Herbul. Did not notice much difference in terms of the shade. It covers the grey well but you need to be patient and let the henna dry properly. The hair looks black and shiny afterward. I do not cover all of the hair just the grey bits. Sometime I use comb but sometimes I use hands to grasp the stands. Then I check that there is no henna on my face, glasses, hands and I clean bathroom before henna has the chance to dry. When I coloured my hair for the first time I did not notice few henna flakes and and really hard time to get them off. I noticed that sometimes the colour stays longer up to 4 to 5 weeks. I guess it depends how long I leave it on and much water I add to it. My experience with henna so far has been very good. It does the job although it takes time and effort to put it on. I am wondering when I get more grey hair if I am going to use it all over as that it will be even messier and harder to do. Not sure yet. But for covering of few grey it really works.
Update: Recently I have been adding couple of drop of the lavender essential oil. The henna mixture by itself has a grassy smell. The lavender helps to perfume the hair and eases itchy scalp.
Update 2019: Tried some other hair colours but this one is still the best and cheapest.