Michael Canalé, Aniston's colorist, is the main person responsible for her honeyed locks. He has been working with Aniston for 24 years and is also the co-creator of "The Rachel". Over the years, Rachel's hair evolved, but it remained highly desirable to many people even 15 years after the final episode of "Friends" aired.
Being in the spotlight with such famous locks means that Aniston has to get her hair colored every five weeks, which is a lot more frequently than the annual treat most people enjoy. According to Canalé, they refresh the color every five weeks, and if anything needs correcting, they take care of it during that time.
Canalé also mentioned that sometimes Aniston has to deviate from her usual color for a movie role, such as in "Dumplin", where her hair was blonder than normal. In these cases, they create a blonder look, and when the movie is done, they have to repair her hair and get it back into shape. Luckily, it usually only takes one or two times to get it back to normal.
