My mother is in her early 60s and colours her hair about every 3 weeks.  I noticed the other day just before, the roots are almost all white.  I can picture her as a 90yo with a head of artificial looking auburn hair and not one grey to be seen.
I'm getting a few grey hairs on one temple so if I leave them I may end up with a Lilly Munster streak, which could be kind of fun.
When do I decide to stop clouring my hair so I can go grey naturally?  My natural very dark hair colour isn't that different to the dye but I still like how the dye makes it so nice and shiny.  Do I keep colouring it all and gradually get silver tips or get the hairdresser to try to not get dye on the grey already there.

I'm not going grey myself...but based on what I've seen on others, I think that simplest and most graceful way is just to decide not to color when grays appear. They will know, where to come, and in my opinion, salt and pepper look is quite attractive if the hair is healthy.

From experience, however, I can tell, that treating your hair gently and giving it what it needs and no more, will give it great shine too.  ;D I'm an ex shine spray user: I liked to spray it sometimes just to get a little "extra" shine. After three months here, I gave it away as obsolete, along with my commercial styling products.  ;D

What I did ... I colored it until when the hair color faded out there was a sharp demarkation that was substantial enough for me to be conscious of to the point that it didn't quite blend in but wasn't yet a straight line.

I miss coloring very much but I like my hair long more so I'm stuck and hoping for when it will be mostly white, which I might add is taking a lot longer than I thought it would  ::)...g

Never coloring your hair is the "best" way to allow yourself to go grey gracefully.  

However, if you really feel you much color, try to keep your color within 3 shades of your natural color.  As the amount of grey/silver increases, you may need to change the shade a bit.  Using henna might be a better route, if you have darker hair to begin with.  The color will just fade out and be less noticable than with a permanent color.

When the time comes that you decide to quit coloring, you will want to try to have your color as close to your natural color as possible.  Sometimes having low-lights will help with the growing out process to minimize the demarkation line that will occur.

Good luck with your growing and color!

you could color with less frequency and go more in the direction of the same shade but with more ash in it. An ashy shade will be closer to the grey. It will blend more that way and then when you decide you don't want to color anymore it will grow out with less visible roots. Depending on what color you are dying it, you could also start incorperating some blue malva conditioner to help blend it as you stop dyeing.

I know this is an old thread, but here's what I did.  When I decided to go gray, I had my hair frosted.  (I had been coloring for years, so it was my last hair coloring venture)  As the grays grew in, it looked very natural.  Now that my hair is down to my waist, I am really proud of my gray hair!