The best tip is you don't want to wash your hair too often. Between the Pronto Colore pen and the dry shampoo, you can postpone washing your hair every day. Instead of washing three times a day, you can wash two times a week. Some clients will also wash once a week using the dry shampoo in conjunction with the pen.
When you start to frequently shampoo, discoloration will come. It also depends on what type of product your colorist uses. As long as you use a good, strong product, a professional product, the color will last longer.
Still, with that, if you don't have frequent color, like on the time schedule, discoloration can happen very easily. Bad shampoo can give a different tone of your color. If you go away on vacation and you're coming back, there's sun versus winter. There are so many elements in place that can create discoloration, so it's very important to keep up once a month, once every 45 days.