There's the old story that having two of everything for precautions sake can never be a bad thing. The other day my card reader broke - in the middle of a photo shoot and for some reason one of the pins dislocated and caused my photos to corrupt when I tried importing them. At that point I really wished I had a spare CF card reader to facilitate the hassle of having to re-shoot the entire thing.

There are photographers who bring two camera bodies on shoots - one with a wide lens and the other with a telephoto lens to make shooting split second moments easier. Those split second moments, I figure is worth about $1,500.00 in a camera body and lens at the very least.

Do you have two of everything? Two cellphone batteries? Two car readers? Two sets of laptop chargers? Two mice and keyboards?