In my professional (retired) opinion, there are a number of things to consider, like:
What color is the grey around your face.... sparkly or battleship dull?
What color are your eyebrows.... getting grey there?
What is your base skin tone? Have you noticed it change?
What shape is your hair in now? Has continual chemical work compromised it?
Would you change your hairstyle if you were suddenly completely grey?
Here's something to try:
Put on your makeup, then wrap a black towel, sweat shirt, whatever you have that's black, around your head turban-style so just the grey shows around your face. Stand back and observe for a moment. Imagine you are meeting YOU for the first time. What stands out? Does the grey throw focus to your eyes? Smile?
My hair was always long and dark brown/black. My intention was to grey naturally, but as that happened, it looked pretty bad and everyone continually said I looked tired...
so I began to dye.
Being in 'the industry' I couldn't EVER attend my clients with ugly roots hanging out of my head, so my touch-ups were frequent... every 2 weeks.
It became a pain in the butt and even with the finest products my hair and scalp were bombarded too often for my personal comfort.
Upon deciding to move to TV, I wore a baseball hat until my roots were grown out enough, gave myself a pixie and styled it disheveled a bit while it grew to a manageable length. It was the most efficient way to make the transition. (especially from my brunette color)
The freedom of it all is a wonderful thing, and my husband loves my new look. In fact, I get compliments on my hair from perfect strangers all the time. It sparkles in the sun and looks even better with a little Florida tan.
