how long shouldi wait?

First and formost
What is your natural hair colour?
I think you can safely wait a week or something.
I might be worng though.

From what I have heard..

3 months is how long you have to wait to prevent any real dammage

6 weeks is ok as long as you don't mind some breakage around the scalp & split ends

1 week is the time I have heard you have to wait before a salon will try anything unless you have an emergency.

for the first person, the ligher shade probably won't make much of a difference over your already dyed hair. I just did the same from a medium red using a level 9 blonde and it only changed enough to lighten slightly O_O There are hair color removers that can be used before the new shade is applied, but I would only trust a salon to do that myself. ^_^;;

For the dark hair, if you want to go much lighter you should probably go to a salon and ask them to lighten for you. It sounds like you may need a double process job.. dark hair is hard to lighten successfully.

Hi Kari,

There is nothing you can do to prevent damage to your hair if you are going to put permanent color on it again. Waiting two days, two weeks or even two months won't make your hair any more resistent to the damage inherent in the coloring process. Simply put, hair is dead and without cellular regeneration there is no way that dyed part is going to be in better shape next season. New growth, however, is stronger. I'm talking about the already-colored part. You might as well color your hair when you want because the amount of damage will be the same regardless how long you wait. I don't mean to cast an inpenetrable cloud over your coloring plans--it's just a trade-off: You can get the color you dream of but your hair will suffer somewhat in the process. If your hair is naturally resilient and not porous, the damage won't be as noticable.

But take note from the above posters: color does not lift color and such efforts are best left to a trained professional. Good luck!