It's best to wait four to six weeks before recoloring hair according to Garnier, a leading manufacturer of home haircolor. This limits any damage that could be caused by dying the hair twice in a short time frame.
Dying hair changes the structure of the hair shaft, giving it a dry appearance over time according to WebMD. It can also cause breakage and split ends. The best way to combat damage is to wait as long as possible between hair dying sessions. Good hair habits also help keep the hair looking healthy when using artificial colors.
After coloring, avoid over-brushing the hair and updos, as both cause breakage. The blow-dryer and flat iron should also be avoided. Both of these devices further damage the hair and cause it to dry out.