The only feature of the tool we haven't discussed yet is the button labeled "zero." If that button is pushed while the calipers are open, the dimension on the screen is reset to zero. It's a handy feature when you're trying to measure the differences in dimensions between to objects. Caliper the smaller one, reset to zero, then caliper the larger object. The figure showing in the display is now the difference between the two objects.
It's also not a bad idea, at the beginning of a session, to close the calipers (gently, please) and push the "zero" button.
Only a few years ago, electronic calipers were extreme hi-tech, very expensive gadgets. (I paid about $50 for one.) Nowadays they're ordinary tools, and extremely reasonably priced. An excellent investment.
Another tool acquisition that I recommend to every scale modeler is a pocket calculator that works in feet, inches, and fractions, and converts between the English and metric systems. I bought a Radio Shack "Decimal-Fractional Yard-Foot-Inch Calculator" about twenty years ago, for about $35, and it quickly became one of the most frequently used tools in my shop. (My father, a retired professor of architecture, drooled over it so much that I gave him one for Christmas.) That calculator must be built like a tank; it still works perfectly. A few months ago, though, I found one that does everything my old Radio Shack one does and converts to and from metric at Wal-Mart for less than $10. I bought one to keep by my drawing table, while Old Reliable lives in the workshop.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.