I use to get my hair cut every 7 weeks and colored every 14 weeks and highlighted every 21 weeks. Now I'm into being cheap (thanks to the economy :) and I have become a DYI in the hair dye department. I have my hairdresser highlight my hair 2 times a year - that way when I color it myself it isn't one dimensional.
It was time - my hair is naturally almost black (it keeps getting darker as I get older - minus the grey hairs), so after a summer of bleach out - proof we had SOME sunshine - it was time because the grow out line was about 2 inches!
With my coupon I got my box o'color for $5 - so I think I just saved about $70!