Spend time at any airline terminal, train or bus station, and it becomes obvious: The world is divided into light packers and "take everything but the kitchen sink" packers.
How can it be that some of us manage a 21-day tour of Europe with a carry-on bag, while others need suitcase upon suitcase for a weekend up the coast?
But those packing habits, say mental health experts, may actually be a reflection of our personal characteristics and anxieties.
"Personality-wise, people who are light packers seem to have anxiety about excess," said Mark Goulston, a Santa Monica, Calif., psychiatrist and co-author of "Get Out of Your Own Way" (Perigee Books). Having too much luggage may, he said, make them feel out of control.
On the other hand, heavy packers probably have anxiety about feeling they might forget something, Goulston said. So they throw in everything they can think of, just in case.
Heavy packers "are probably not the greatest planners," Goulston said, while light packers have a reputation for being efficient and anticipating what they will need while away. Heavy packers are often more people-oriented and concerned about pleasing others, he added.
Of course, there are plenty of practical reasons to pack as little as possible, given the possibility of misplaced baggage or long lines at both baggage check-in and claims. Travelers' packing habits are also related to their "presentation of self," according to Jeanne Curran of the sociology department at California State University, Dominguez Hills.
"If you're really secure," she said, "it doesn't matter what you wear (while traveling)." While Ms. Curran said she admires light packers, she isn't one. On a typical one-week trip, she will take two suitcases. "But it used to be three."
And of course, she has logical reasons. "I (often) travel with my husband, who likes elegant restaurants," she said. To her, that means many changes of clothes and the need for jewelry and other accessories. Once at the destination, she likes a big choice of wardrobe so she can dress according to her mood. "You are going to feel bad if you don't look your best."
Light packers, Ms. Curran speculates, carry little luggage partly so they can feel free and bypass any hassles at baggage claim areas.
Those distinctions make sense to Arlene Kraushaar, a Beverly Hills, Calif., marriage and family therapist on staff at Century City Hospital in Los Angeles. "Heavy packers think they have to be prepared for everything," she said. "Light packers want to keep things as simple as possible."
Donna Cruzan of Toluca Lake, Calif., a veteran traveler who generally takes about five suitcases for a two-week trip to Europe -- including one suitcase solely for shoes -- says that being prepared for the unexpected is one reason for her packing habits. "You never know. You could spill. Something might rip." The weather could change quickly.
On the other end of the spectrum is Kay McDonald, 52, of Burbank, Calif., who takes only a large backpack when she travels and hasn't checked airline baggage in 10 years. "I want to wear my luggage," she said. "I like free hands. I don't want to ever stand in front of that baggage carousel again."
Light packers often marry or befriend heavy packers, Ms. Curran said. Her husband, a light packer, indulges her habit, she said. Often, Kraushaar finds, heavy packers who travel with light packers pack less and less over the years.
Not that one packing preference should be deemed superior to the other. Said one mental health expert: This shouldn't be about bashing heavy packers or light packers.
Even so, Ms. Kraushaar, a self-described heavy packer, couldn't help mentioning a difference she has noticed. Light packers tend to brag about their lack of luggage and to tease heavier packers about their excesses, she said.
Not so their opposites. Asks Ms. Kraushaar: "Do you ever hear a heavy packer say, 'I took 18 bags to Europe'?"