I stopped dyeing around 5 years ago, around age 46. I had dark brown hair, dyeing to match original colour as much as possible.
I did the cold turkey method. It was only really bad for a couple of weeks, around week 3-5 (I had fast growing hair, so my skunk stripe would start to appear only a couple of weeks after dyeing, and I would have to dye every 3 weeks).
Dye fades relatively fast, so while my grey was growing out, the rest of my (long) hair was fading to a light brown and then kind of off-blonde colour. You could definitely see what I was up to, but that's what made it bearable, that I didn't look unkempt or dishevelled after week 5 or so. I was just obviously transitioning to natural, and several strangers complimented me on the new colour. After a couple of months the tone of the dyed and undyed hair more or less matched, although the bottom was blondeish and the top my new fabulous rockin' grey.
I did it this way because it was the fastest and least damaging way to get to pure natural hair. I researched quite a bit before doing it, and other methods looked expensive, unreliable, and risked putting me back at square 1. I probably would have cut it short to speed things along if I was single, but my husband strongly wanted me to keep it long, so I did.
Good luck to anyone taking the grey plunge, grey hair is amazing and I don't regret it, although I do look older. And in the frugal realm, I started getting occasional unsolicited seniors discounts at stores! (I don't look that old, but if teens are working then everyone over 30 looks old, and if we have grey hair, automatic grandma status! :-D )