i'm not a colorist, but i will share my daughter's experience.
like me, and my father before me, she is graying early, started at 17. so for her wedding 4 years ago her friend who is a colorist did a 'TEMPORARY' color to cover the gray.
ah, she finally cut it all out last year. (it had oxidized and was orangey.)

my hair was darkest brown/black, and i bit the bullet and went cold turkey to transition. happy i did.
[FONT="Arial Narrow"]
3a, some 2c & 3b, medium texture, porosity normal, low elasticity
washing/cowashing, conditioning, protein tx: curl junkie products
leave in:cj conditioners and treatments as leave in
styling: cj pattern pusha, cj honey butta leave in, cj cccc, cj ciab, lalsg. cj aloe fix gel is my high dews/summer HG!!
sealants - spiral solutions emollience butter, jane carter nourish & shine