How long should I wait before I can bleach my hair again?

My hair has been through a lot dyeing-wise.
January 2005 it was jet black, June 2006 dyed dark brown, that faded to a medium brown over summer, at the end of summer the top was bleached and tinted and bottom dyed black, the top at first went ginger but is now blonde.i'd like it bleach blonde though (and still black underneath)
it's been about 3 months since it was dyed.and i have about an inch of routes..
is it too soon to bleach the top again??
(oh and its not in AWFUL condition either, well - it's not breaking..)
Answers:
Bleach will always remain in your hair no matter how long you wait to bleach over it again. Your hair is not breaking now, but it can be at its stretchy stage and then the 2nd bleach application you put will break your hair off..you say your hair is always blonde but you want it blonder..go to sally and buy a platinum toner with a 20 volume and leave on your hair for about 7 min it might leave a lil purplish tint but that will wash away on the next wash..you dont need to rebleachyour whole hair just touch up the roots and tone.
Hi,

Dyeing your hair dark adds colour and bleach strips it away, so seeing as you have dyed it dark a lot probably means you can bleach it again whenever you want to because the hair doesn't sound damaged at all. I've been bleaching mine for about 3yrs straight and my hair's fine.
maybe you should let it grow out to be your natrual color first and then start dying it again
♥no its ok to bleach .3 months is fair
The rule of thumb (as I was told) is that you should wait 1 to 2 weeks between colorings after the first time to avoid damaging the hair. After that, the more you do it, the more damage it will cause (regardless of the amount of time in between - unless it's grown out). I was also told that you can't bleach hair that has been dyed with a permanent dye (but you can if it's semi-permanent). Things may have changed since then (I was told this about 2 years ago) - they may make a permanent hair color stripping chemical but at the very least, you would have to first strip the permanent dye off before bleaching (if they do in fact make such a chemical for stripping permanent hair color).

By the way, I don't think using bleach on permanently dyed hair is impossible - I think the issue is that the amount of processing required to remove permanent dye with bleach damages the hair.
Just bleach the roots. get a kit (or asmall brush) put bleach on your roots - leave it for about five minutes short of the whole time you normally leave it then add the bleach to the rest of your hair, massage it in and leave it for last few minutes - and there you go - great blond hair.

Or another way if you want to keep the roots dark.. buy a streaking kit - but pull near enough all your hair through - this will keep the roots away from the bleach.