I dye my hair black with permanent dye. I've tried the cheapest to the dearest and most inbetween but it still washes out and fades really fast, making my greys reappear faster than I'd like. So, fed up with trying not to wash my hair too much and colouring too often (min every 2 weeks, max 3) I think I've finally found a helpful solution. Condition first then shampoo. My hair is clean, soft and shiny like it usually is if I do it the other way around but I'm losing very little colour now, like 90% less.
It's a pita isn't it. I also tried to use the gentlest shampoo possible, usually a baby shampoo but it still happened. I'm going to try it with pantene or tresemme in reverse. I love those but stopped using them as they seemed to make more colour strip out.
Hope it helps you too, come back and report please
Are you dyeing all the hair each time with permanent dye? If so that is your problem
Try doing only the roots with the perm (literally just the regrowth) and then use a non permanent dye on the rest of your hair. It is already dyed and doesn't need to be dyed again, just have the colour enhanced. I cannot tell you how much difference this has made to my hair. My hairdresser told me this - if you are hammering your lengths with harsh dyes every time then they won't be able to hold colour and will fade.
The other thing that makes a big difference is mixing a bit of macadamia oil (half a tsp or so) in with the dye. This makes it last longer.
My hair has now got to the stage where I just need the regrowth doing every 3 weeks and the rest of my hair holds the colour, I only need to put a non perm one through every 6 months, if that.
No, I mostly just do the root, my hair is very very short anyway, but I probably do touch the rest of my hair in some places but don't intentionally cover it often. My root area loses the most colour, I can visibly see it getting lighter after a few washes I've never tried the oil before but hopefully now my hair dye will last a little longer.
Someone on here mentioned ( think it was Tatty of old )pre-treating grey with peroxide because it opens up the cuticle and allows to dye to penetrate so it sticks around. I think 20% vol was mentioned and leaving it only on the grey roots (so apply with a cotton bud) for 10 mins and then popping the dye on. In the last couple of years something has changed with respect to the durability of all the home colourants. Even l'oreal Excellence isn't as reliable as it used to be and the Preference one is now rubbish.