Oh, from riding my bicycle I've made a few realizations.

Riding with a very dim headlight. Ok for the most part, but one's eyes get dark adapted. And, then get blasted with high beams, and one is completely blind.

If I ride with a brighter light, then I'm not as much dark adapted, and don't get as much blinded when a car comes at me with high beams on.

Plus, cars respect bright lights much better than dim lights.

The one rule with riding blind...

DON'T RIDE TOWARDS THE LIGHT!!!

Focusing to the side of the road helps a lot, but only if there is a fogline.

Those roads without a fogline can be quite dangerous when one is blinded.

It is hard to say how much light is needed. I've seen bikes with dim headlights/taillights, and they really don't catch one's attention as much as a good bright light... Without blinding other road/trail users.

If you have a "Daylight Taillight", then step it down a notch at night.