Nobody likes roots, right? The hardest part about coloring your hair is the way it starts to look about 3 weeks after you have it done.
Colour Touch-Ups are needed every 4 to 6 weeks as root color grows out. A visible line starts to reveal itself, distinguishing your natural color and the hair color your beautician applies in the salon. The longer you go between color visits, the more obvious the line of demarcation.
Professional hair color and the kind you buy at the store have different ingredients, which can sometimes interact badly. So it is better to have a color touch-up done by a pro at a beauty salon.
Also, if you're getting a weave, it's very difficult to duplicate that yourself. It's not a good idea regardless. Talk to your hairdresser about changing the highlights a bit so the roots come in less obvious.