i always have 1 light on me. sometimes 2.
i too carry a backpack to work everyday, or at least 5 or 6 times a week.
i have my olight m20, quark 123-2, and jetbeam lll M, backup primaries and alkalines, my PSP, ipod, earphones, leatherman wave, spyderco salt-1, baseball cap, beanie, rcr123 charger, lotion, lipbalm, band-aids, sunglasses, toothbrush, a novel, work ID, and some spare change in my bag.
jetbeam RRT-0 in my pants pocket, and zebralight in my shirt pocket.
during work ill carry 2 or 3 lights, i like to switch them up, and carry different lights for different purposes. i always have my RRT-0, and
zebralight, and ill switch off between the quark, jet lll M, or M20.
many nights ill let a co-worker borrow a light, usually the quark or M20, in hopes that i can turn them into a flashaholic, or at least dump their p.o.s light and get something better, since this is our most used tool at work, i believe getting something of quality and better to use is a must.
i helped a friend buy a jetbeam M1X, its on the way now. its mainly because of the constance trash talking a sercurity worker, and myself included inflict on him everytime he turns on his $15 light. :twothumbs but its alright, ive known him for over 20 years.