Both, as I've said in numerous other posts I have four Cateye Uno headlights on my bike, two are on the handlebars, and two are on the front fork. I have three (three different) Cateye taillights. They are:

a Rapid 3
a TL-5
a TL-3

I also have a Light and Motion Stella 150L headlight mounted to my helmet that is used at night, I also have a PBSF mounted to the rear of my helmet that is on day and night, I also have another red flashing light on my right seat stay, as well as a white Serfas light hanging on the left side of my top bag.

All flashing lights are on day and night, and with the exception of the two lights on the sides of my bike they use either AA or AAA batteries. The other two use two 2032 batteries as do my two bike computers.

I also wear an orange safety vest day and night.

And also given that as I've said before I've only received one negative comment in regards to my lighting.

So why not use lights day and night? Why not wear a safety vest? Why not wear clothing that is as noticeable as possible?