While buying new luggage for a business trip to Punta Cana, we learned of a change in the allowable size of carry-on gear that somehow made it under the radar without much fanfare. The revision of as little as one inch from the former standard 15" width to the current restricted 14" measurement for carry-on bags can mean the difference between whether you're permitted to bring your small suitcase, duffel bag or other luggage with you aboard the aircraft or if the airline personnel will require that it be stowed with its larger pals in the belly of the beast.
Don't assume that you'll be able to sneak by just because your bag is a tad too big. In some cases, passengers have been turned away by TSA
agents while waiting on line at the security checkpoint and forced to return to the airline's check-in counter (and its sometimes long line) to have their oversize bag tagged and checked as luggage. Travel is stressful enough. This added anxiety is annoying at best but, most importantly, the unexpected delay may cause you to miss your flight.
Being an informed traveler means less hassles at the airport.