I'm about 60 40% grey and have been having my colour professionally - ahem - enhanced for 'some' time. I'm a natural dark brunette and have a full head tint in pretty much the same colour.
But times is 'ard. Woe is me. And I want to stop tearing my hair out. Literally colour my roots myself.
BUT WHAT COLOUR SHOULD I BUY?!?!?
Honestly, I am BAMBOOZLED!
Am I a 4? 4.5? 6? Dark golden brown? Natural brown? WHICH??? 
What I'm most scared of is mismatching the colour - my tint is ever so slightly lighter just past my regrowth. It's just slightly more.... Um...'gold' whilst still dark brown. Apart from at the front, under my fringe (where the fairies deigned to make me go very grey
). I have very little grey in the length of my hair (chin length bob).
I think, think, my colourist said I'm a 4.5. But it may have been 4.0 (I know about the .number being tone) and I know I need a permanent to get the colour to stick.
BUT WHICH ONE?! There are just so bloody many options!
Help, Good People. Help.