Ive never lightened my whole head its not something that appeals to me but highlights r nice when they are done properly and not streaky. My sisters prefer my hair lighter on me it just took me a while to get used to it
I had a ash blond/caramel mix they did add bleach to my hair to lift it and then a toner to allow for the color to settle.
As with any hair color just important to keep it well conditioned regular trims and go easy on the heat! I went on holiday a few weeks after and my hair became even lighter so i just went and had a toner put on to darken it abit.!
But if ur seriously considering going light all over start off with a softer brown and then work your way down