To begin with the choice of colors would top the list. So what family of colors is on your mane wish list? Are you looking to alter the color or color the gray?
But any such stigma associated with coloring our mane is long gone. Anymore it's so common no one gives it a second thought. In fact some of us would be hard pressed to recognize our own natural hair color it's been so long since we have seen it. Because as they say color is a girl's best friend.