I have a dial caliper that I use to measure OAL on my reloads.
Sometimes it seems that a micrometer would be handly when I want to measure bullet diameter or maybe the case mouth diameter when I 'm setting the case mouth expander die....yet the dial caliper will sorta do this as well...I guess its a matter of accuracy.
Which brings up another subject...what do you use to "calibrate" your calipers with guess a gauge block is in order here.
http://longislandindicator.com/p164.html
Guess there is no end to the "toys" a reloader must have!