The sun went behind the rococo colonial cathedral while a couple of gorgeous big-eyed teenaged girls debated buying my red polyester blend shirt. With retail clothing experience, I stressed the shirt's wash'n'wear and colorfast attributes, in mangled Spanish. They bought, and walked off happy. But as I counted my coins, I had to wonder what I was thinking when I packed.

Overloading is one of the most common errors we make when we travel. We end up lugging around a heavy load of things we'd dump if they hadn't cost us so much.

Why is the over-packing habit so hard to shake? Do we think human needs can't be met in far corners of the globe? Are we such hopeless materialists we think stuff is the answer to all our fears? Or do we go into minor panic just before departure and imagine some item might prevent suffering? Preventing suffering is what packing light is really about, avoiding the misery of hauling around heavy stuff you don't need or want.

I like to get on and off planes, trains, boats and buses and in and out of taxis carrying all I possess. The moment you are separated from your belongings, something can end up missing. I also appreciate being able to walk from the station to a place to stay in small towns or large cities.

Before I go any farther, let me point out that if you are in Paris, Tokyo, New York or other fashion capitals for several weeks, that is NOT traveling. It's staying. Different rules apply. In major urban centers, looking good is your ticket to a good time and interesting new friends. So, don't skimp on style and class. On the road, you change your identity, transforming into a good animal on the move.

I must also point out that though males also pack too much, they seem much better than females at getting along with very few practical clothes. Males go overboard with gear - water filters, cook kits, fancy photo equipment, snorkeling gear, mini-computers and such. Most of this advice is aimed at women.

This leads back to the lightness factor. I've been to fifty countries, hitch-hiked around Iceland, ridden a camel across the Rajastan Desert, grabbed a jet to Costa Rica on two days notice. This is no novice traveler speaking. Yet, despite knowing what a burden luggage can be, my instincts tell me to be ready for anything. In other words, cutting to a minimum is not second nature despite plenty of experience.

Recently, I taught a four-hour class I called "Cheapskates in Paradise". It included discussions on packing. Students commented that this part of the class was both very entertaining (as I unpacked and spread out), and very useful.

For the first class session, I walked in and announced that I was ready to go to Europe in the spring and camp. The actual trip was a month with my pal, Marti. In class I unpacked a rolling carry-on bag stuffed with a four-pound tent, air mattress and light down sleeping bag. My daypack held clothes, camera, journal and guidebooks. I wore a coat, wool pants and waterproof clogs since it can be cold and wet in Europe.

As for the trip itself, once in the rental car, we had spread out into cardboard boxes we picked up at the first grocery store. We each set up our own food box, too. And we still had plenty of room in the car. We camped through East Germany, Czech Republic, Poland, Slovakia and Hungary in May and June, staying in hotels about one night in three. One day we climbed the fence and spent a whole afternoon exploring an abandoned Soviet military base, and we both found some really cool mementos to bring home, like a menu board in Russian. We were glad we packed light and had room for them.

For the second session of the class, I brought a daypack and tote. "I'm going to the west coast of Mexico for two weeks in February," I announced for the sake of drama. In real life I went with Carol, my best pal from eighth grade, and her friend, Dawn. Carol brought one of those roomy rolling backpacks filled to capacity with everything she could possibly need - maybe fifty pounds, including six books. Dawn packed a little lighter, but not much.

Walking in and out of villages off the main road, hopping on and off local buses, riding in pickups, climbing to the third floor of fine old beach hotels – these were times they really envied me my light load. And not once did I wish I had brought more. In fact, at one hotel I left several garments behind, drying on the line on the roof. Though I missed the items, I got along with even less that I had thought possible. A good lesson. My oversight left so much extra room in the daypack that I bought a colorful string hammock to bring home.

On the road, having just what you need and not one thing more makes life easy. The freedom of being unburdened is marvelous. But the art of light packing is not easy for most of us. The secret for me is to pack with extreme care.

Here are my rules. No garment clashes. All tops and bottoms are totally interchangeable. For warmth, use layers. Every item has a dual purpose, nice enough for dinner downtown but tough and simple enough for hiking. The tropical daytime sun shirt becomes the party shirt at night.

Personally, I add one more challenge to the acquisition process. All the clothes I take must come from second-hand stores. Clothes, especially when worn day after day and beaten clean nightly in a washbasin, wear out quickly. I always seem to sit in something messy, spill my lunch, have a darling baby burp all over me, or snag on a thorn bush somewhere along the adventure trail.

Besides, who wants to look rich and tempting to the bad guys? Which brings me to jewelry. Leave it behind. Take a five-dollar water-resistant watch with an alarm. If you want to look gorgeous for that one night at the opera, fake it with cheap stuff or a nice scarf.

Is this getting complicated? Well, if you think now, you don't have to later.

For the tropics
I have one set of clothes for trips that include good beach hotels and nice restaurants. Style, color and versatility rule with this "collection luxe." A second set is for tromping through the Yucatan jungle and climbing pyramids, or for kayaking and sleeping in beach shelters in Palau. For this "collection gauche," toughness plus sun and bug protection are prime considerations. Most tropical trips require some items from each of these two sets. Both fit in one cardboard box.

For temperate climates
Add a light wool sweater, tights and solid shoes. I add and subtract as I make good finds at the various cheap-chic emporiums.

The winter collection
This is another story, much harder to keep lightweight. I spent November in Japan with one bag so it can be done. A down coat, warm tights under wool pants, thick wool socks and a cozy hat were the only additions for a mild winter, though I wished for mittens that night in the thatched-roofed traditional house without heat high in the Honshu mountains.

Every ounce I pack I regret having to carry at some point in a trip. On a recent adventure, I made a list of what I actually used, to remind myself of what to bring next time. I used a Cordura daypack with most of the weight on the waist strap. This pack could go on walks with me once I got settled. A small fanny pack was my purse, and a nylon tote that held my clothing en route also served as a shopping bag when I hit the markets.

Clothing
(for cool climates)

• Loose, light, black long pants nice enough to wear out in the evening and for keeping the mosquitoes off after dark
• tights to go under pants when it's chilly
• quick drying, modest, long shorts in khaki color
• swim top to go with shorts
• light skirt or culottes when you want to look more feminine
• one or two colorful t-shirts
• short-sleeved poly shirt or tank top to wear under anything
• quick dry dress up shirt
• long sleeved, light color
sun shirt
• white suncap
• head scarf for wind and to dry hair flat
• two or three underwear
• two pairs of quick-drying socks
• light running or walking shoes (wear on plane)
• all weather, synthetic (not leather), black walking sandals
• coated nylon windbreaker with tie-tight hood
• thin black acrylic or wool knit sweater (wear on plane) that can go under a shirt and windbreaker when it's chilly

(for cooler temperatures)
Add the following and you can layer up using just about everything you brought.

• wool socks to wear with walking shoes
• Polypro undershirt with long sleeves in a dark color

Personally, I don't see cold weather travel as much fun. But for the high mountains, or visiting Patagonia, Siberia or Scandinavia in summer you really will need a slightly larger rolling suitcase or backpack. With down and synthetic materials you don't have to haul a ton. I add black wool pants which go anywhere, a pile pullover, black down coat, and boots that beat the rain and ice. If you plan to be outdoors a lot in rainy weather, take a totally waterproof rain suit that goes over your pants and coat. It worked for me in horizontal downpour on a fishing boat off Alaska.

In addition to clothes, everyone needs some toys. I won't visit a warm ocean without swim goggles, the one indispensable item for exploring coral reefs. The snorkel is optional, swim fins way too heavy.

Comfort and care supplies

• bar of glycerin soap for skin, hair and clothing, baggie to store it
• nail file, tweezers, tiny scissors, mini sewing kit
• comb, razor with blade cover, toothpaste and tooth brush
• sunscreen, SPF 30 lip gloss, small Vaseline for dry hair and skin, insect repellant containing Deet

You can buy bottled water almost anywhere these days. I always carry a water bottle. I find that one liter is plenty except in extreme heat. Iodine pills are invaluable for sterilizing questionable water, which to me is water in any less-developed country, unless bought sealed or have personally seen that the water was boiled. With my water bottle and pills, I can fill up in a bus station bathroom and have safe water. A medicine dropper in a small bottle of plain bleach does the same job as chlorine, two drops per quart. Then wait 30 minutes.

In many places the available cuisine may wear thin - fatty, salty, or just plain boring. I like to supplement with my own salads of fresh peeled fruits and vegetables from local markets and vendors. Soak all raw foods you don't peel in your Iodine water or Chlorine water about thirty minutes before eating, to kill gastrointestinal bugs. I carry a pie tin, plastic fork and spoon, folding knife and film cans of salt and of mixed spices.

In all of North and South America, plus American-influenced-Pacific Islands, the same electric system is in use. You may want to take an electric mini pot, for sterilizing water for making tea or coffee in your room. In Africa, Australia, Europe and Asia they use a different current, so buy a pot when you arrive.

I am a recorder of memories, so I carry a compact 35mm camera with flash which will shoot slides or prints. One of my weight extravagances is plenty of film, which is costly in less-developed areas. The camera goes in my small tummy pack, along with a little note pad and pen. In the back pocket of that tummy pack, I fit my passport, travelers checks and credit cards. These never leave my body en route. I have a tummy pack large enough to fit a small paperback book too, because you never know when you are going to be in for a long wait or quiet evening in your room. In my daypack, I keep my serious diary, extra pen and pencil with an eraser so I can amuse myself with sketching. An address book and a few envelopes are valuable. For mailing stuff home, or keeping brochures in order, I prefer big Tyvek envelopes. And I love to have a mini phrase book for the local language.

In the medicine kit (a small zip-lock baggie), I carry cleansing wipes, a small tube of topical disinfectant and five or six band-aids. Wounds infect much more easily in the tropics. Aspirin is nice to have, as is Vitamin C in case you feel a cold coming on. Zinc and beta-carotene also inhibit viruses and you're sure to be exposed to some new ones in a new place. Motrim for stomach upsets is always useful. Anything more is excessive unless you are going to be far from civilization, in which case none of this advice is too useful.

In many parts of the world you can walk into a pharmacy and ask for any medication available, or get the pharmacist to prescribe based on symptoms. These guys are usually pretty good. Go to a doctor if symptoms persist. In seriously disorganized areas of the world, you definitely want to have a couple of sterile syringes along in case you need an injection. If you require any uncommon medications, carry them with you.

Wow, that all sounds so complicated and the lists look huge. But you'll be amazed at how little room it takes. Practice thinking need, not want. Give yourself permission to leave things behind for the hotel maids if you overpack. They usually appreciate it.

Joyful traveling.