On a older version of Volvo S60, you can set the lighting's brightness on your own by scrolling up or down on the right hand side just where the Headlights option is. Do most of you set it to the highest ( brightest ) ? Some people advised me not to set it to the brightest because it eats up battery, opinions?

then better not ON the lights... saves way more battery power....

I'm not talking about the headlights, I'm talking about the lights for the instrument in the middle, that will light up automatically when it's dark. But the brightness you can set it manually, I'm asking if I should set the brightness to max or should I not.

Set it to what you need. End of story.