Measuring Tools

Best for: Measurements inside door and window frames, bookcases, cabinets, and other built-ins.

Look for: 6-inch metal slide, the most reliable way to get an accurate inside measure. After you've unfolded as many segments of the rule as you can, extend the slide and add on its measurement.

Shown: Folding 6-foot rule with slide, from Lufkin; about $16; amazon.com