I wash my hair every third day, and don't do the rinsing/conditioning on the off days. I put my hair in a shower cap when I shower on the off days. Washing my hair less often keeps it from drying out, and helps the color last longer.
If my hair is a bit oily on the off days, I put a little bit of baby powder on my hands and fingers, and rub my hands over the part line, hair at the edge of my face, and run my fingers through my hair to distribute it at the roots all around. I just do a little bit of powder at a time. I then brush my hair really well to work it in, and to make it not look like I have powder in my hair. No one has ever said anything about my hair looking odd, and I work with people who would say something if it did.
I actually get more compliments on my hair on my off days. On those days, I just run the chi iron over my hair to straighten it out a bit from sleeping on it. And of course, if needed, do the baby powder thing beforehand.
Maybe I can get away with this since I don't use a lot of product in my hair. All I use is a bit of flat iron spray between blow-drying and the flat iron, and then a very light mist of L'oreal Elnett hair spray.