When do you shampoo after you color your hair?

It depends on the dye you used: if it was temporary when you shampoo your hair the dye will wash out straight away. If it is semi permanent it was last 6-8 washes, if it is a quasi permanent you get 12-24 washes and if it is permanent it won't fade. So depending on how long your dye will last you can wash your hair when you like.