I’m packing for a trip and going through the computer bag I carry with me all day, every day. In addition to five pens and two mechanical pencils, I also have three iPhone AC adapters, five iPhone / iPod / iPad USB cables, three iPhone headsets, three “regular” sets of headphones, six AAA batteries, and two USB automobile adapters.
Why, yes, I was a Boy Scout. Be prepared.
Update May 13, 2024: Twelve years later and I am still generally over-prepared. I have no less than six USB-C to USB-C cables, two USB-A to Lightning cables, a USB-A to USB-C adapter, a multi-port Apple adapter (HDMI, USB-C, USB-A), three USB-C power blocks, a USB-A power block, a backup battery pack, my Apple Magic Mouse, my Apple AirPods, eight (eight!) pens, five different notebooks (three are Field Notes), at least a dozen Band-Aids and assorted medicine (Tylenol, Advil, Alka-Seltzer Plus Cold Medicine), and a ton of other stuff.