This is an interesting thread- now that daylight savings time kicked in, I've been paying attn to the bicyclists I can and can't see well to see how much stuff they have. Large reflective stripes catch my eye as well as a red taillight, tho some of those were half obstructed. During the day, I'm just always watching for them, so I'm not sure hi-vis helps me see them, but for those drivers who don't ride...

I'm curious if you ride with a backpack, do you have reflective ones? Might just get out the stapler and some reflective tape to add to mine- it's got thin piping in some of the seams that's reflective, but probably not enough. Or I could hook an extra taillight on there.