Q. I recently took a trip where I was dangerously close to being overweight with both my checked bags. With this in mind, I weighed both my bags with a certified scale before leaving the house and found that both bags weighed in at 40 pounds. When I got to the check-in counter, however, my first bag weighed in at 57 pounds on the airline's scales, the other at 42 pounds. Obviously, I switched some things around to avoid paying an overweight bag fee. Is it possible the airlines' scales aren't zeroed automatically, or accurate? Or is this a conspiracy to add overweight bag fees.

A. Like any scale, airline baggage scales are not always accurate, and more local authorities should make a habit of checking and certifying airport scales on a frequent basis, especially as airlines add and increase bag fees. Airfarewatchdog.com recommends that frequent flyers who check bags often bring along a portable baggage scale when they fly. We've been testing the Balanzza Digital Luggage Scale and find it highly accurate. Amazon.com sells it for $16.99, but you can also probably find it at local luggage stores. It weighs just under a pound, measures up to 100 pounds, and can measure both pounds and kilograms.