How long should I wait to highlight?

How do these celebs do it?  They go black for a movie and it seems like they are blond again next month AND their hair looks healthy. Examples are Reese and Charleze.  We all know Ashley Simpson's hair looks like hay - but how long do these girls really wait before they go back to blonde?  It doesn't even look like Reese went back in stages.  I had my previously highlighted hair coloured brown underneath about 8 weeks ago and want to put the blond back in back but dont want to sacrifice the health of my hair - Any suggestions?? 

Well, I guess when you pay around US$500 solely for a haircut, it must mean your hairstylist is REALLY good.  Some stars do change their hair color often, but they're probably in the hair salon getting a nice deep conditioning treatment once a week, if not more.  That's the key to healthy hair, you can't just fill your hair with chemicals and then think it'll be nice and healthy like it was before.  Your hair texture and need will change, so always keep up to date with the condition of your hair. 

How long you should wait to color your hair again really depends on how healthy your hair is at the moment.  I say deep condition your hair once or twice a week for a few weeks before going for the bleach.  That way your hair will be a lot healthier and stronger to withstand the bleach.  If you feel your hair is still relatively healthy and can't wait that long, then deep condition for a couple of weeks and go for it.

Here are a couple of tests to help you determine the health of your hair:

To check for resistance:  Get a strand of hair and hold it in both hands and then pull it apart, as if you were trying to break it.  If your hair breaks without resistance it is weak, if it seems to resist a little before it breaks it's more resistant and so on.  The more resistant the better.

To check for elasticity:  Again, holding a hair strand with both hands, lightly pull the hair, not trying to break it.  Then bring your hands back together.  Your hair should stretch and then return to it's normal form when you stop pulling.  The less elasticity your hair has, the more dry it'll be.

To check for porosity (sensibility):  Hold a strand of hair and run your fingers through it, from roots to tips.  Then, run your fingers through your hair from tip to root.  If your hair glides with relative ease from tip to root, then it's less porous, the more unsmoothly your hair glides, the more porous it is, meaning your process time (for the hair dye and bleach) will have to be less because it'll penetrate faster.  Do this test on three strands of your hair from three different places of your scalp.  The less porous your hair is, the better.

Whatever you decide to do, just remember to deep condition your hair once a week, it's the key to healthy hair.  Also, for more complex processes like these (bleaching, highlights) I recommend you have a hairstylist do it.  Do your reaseach and find a good one, they will know how to properly color your hair while trying to do the least damage.  Good luck.