I’m a year-round bike commuter in St. Pail, MN. Yes I rode two weeks ago during the vortex. On those cold days my commute takes an hour one-way. That’s a lot of exposure. My headlights are flashlights. I ride with three Convoy S2+ lights with Biscotti firmware. I use cheap mounts from China that I attach to my bars with hose clamps. This mount is more discrete and clean that most commercial setups. The lights are held in the mounts by Velcro straps that I make myself. Yes, sewing machine, nylon straps, steel fittings, Velcro, reflective tape. Very effective. The mounts are such that they will hold the light in place without the strap. The strap makes it so the light won’t fall off if I pick up my bike and fling it down the stairs. Two lights are on my handlebar, one is in my bag.

why?
1. NUMBER ONE REASON - I need to be able to mount and remove the lights while wearing extremely thick mittens. This is because I park on the street but also because I park all over the place. Lights come with me.
2. Parts are interchangeable. I can swap out lenses, reflectors, batteries, tail pieces, switches, springs, drivers... whatever.
3. Biscotti firmware is customizable - brightness, blink pattern if your’re into that, etc
4. I have a stable of bikes and the lights can be put on any bike because mounts are unlimited.
5. Battery charging is annoying but I have a routine. Plus I can carry backup batteries and have freshies in chargers at home and the office.
6. Mounts are attached to bikes very firmly and securely, but I can easily aim them up or down. They do not shake or move AT ALL unless I want them to and then they move very easily.
7. People mentioned the 2 fish blocks. Those are handy and I can use them on random bikes or give them to friends to use with my lights. I keep two of these in my back for backup purposes. As with my mounts, I make my own straps.
8. I have not found a commercially available light with a shaped-beam that meets all of these criteria. The round beam is the only downside for me and I get over that by aiming.

I ride with a Blackburn flea in my helmet that I fire on blinkie mode when needed.
I ride with a Dinotte tail light.