I have read a lot of people saying you don't need to sand the headlight and others say you have to sand the chrome off. If you're going to paint your headlight assembly inside, do you sand the chrome or not?

I understand why to sand, but many say don't and my thought is how long does it last if you don't?

 

If you're speaking about the reflector part of the headlight, don't do that. You'll compromise the light output. if not, then prep everything that you'll be painting or it will fail.

 

Yes, sand the entire chrome insert, but leave the ripple reflector section that's about 2" x 2"
Is that the part you mean?

 

Before any sanding, you may wish to try rubbing tooth paste.
They work on mine when they are about to get bit oxidized. I then finish with wax and they are rejuvenated.
Good luck