Another pressing beauty issue...

"It depends on the growth rate of your hair," says colorist Giselle of the Pierre Michel salon in Manhattan. "You should go in for a highlight application every two to four months, and single process color application about every six weeks."

Giselle, who has pumped up the blonde in such actresses as Sharon Stone and Renee Zellwegger, also says, "During the summer hair grows faster, but it also naturally lightens up, so you don't have to get your highlights done as often as during the winter."