I use both a handlebar light and a helmet mount light on my dark rides. The helmet-mount is very helpful to pan across motorist's faces/mirrors when I am at intersections, to get better view on turns and curved roads, and to look for deer or other varmits that are about to run across the road right in front of me. They are also useful for seeing what you're doing if you have mechanical problems (flat tires).

My routes include some 30+mph downhills and it's too exciting to outrun my lights in the dark. I also credit the longevity of my tires/tubes/spokes to being careful what I roll my wheels over.

The handlebar lights seem to suffer more problems from road buzz.

I also like having 2 lights in case one fails or if a battery dies mid-ride, particularly the rear lights. Shop for lights with sufficient runtime and some surplus in case you are on the roads in the dark longer than planned.

I wear reflective ankle bands. The pedaling motion distinctly identifies you as a cyclist, not a far-away motorcycle or an inanimate construction barrel. Spokes reflectors also help motorists understand what they are seeing.