I had my hair colored Tuesday evening and waited until last night to wash it. I will say I didn't notice as much color run-off as I usually do when I wait only 2 days. My hair is dry and curly and I wash it every 2 or 3 days anyway or I turn into Roseanne Roseannadanna (kids, google her or ask your parents)
I run conditioner thru it ( not what comes in the box, my biolage) right after I rinse the color, and run conditioner thru the next day, then wash and condition as usual after that.
I try to wait a couple of days because it was drummed into my head for so many years that you should do so. My stylist says this is totally unnecessary.
I wash my hair every two to three days, which is the same amount of time I wait to wash it after coloring, sometimes a little longer. If it really needs freshening up, just rinse and condition and don't use shampoo.