After fourteen countries and one disastrous lost-luggage incident in Madrid that left me in the same shirt for three days, I have settled on a system. It fits two weeks of clothing into a 40-liter bag, and it works in every climate I have tried.

This is not minimalism for the sake of minimalism. I do not believe in the cult of “wearing the same shirt every day for a year.” I just believe in not paying twenty dollars to check a bag, not waiting at carousel six, and not losing my luggage in Madrid ever again.

The bag

Any 40 to 45 liter backpack or roller will do. I use a soft-sided 40L backpack because it fits any overhead bin from a Boeing 737 to a regional ATR, and I can sling it on for a long walk to the hostel. If you prefer wheels, look for something under 22 inches in height. Both work. Pick the one you will actually carry.

The clothes

Two weeks of travel needs:

• 4 t-shirts. Two in dark neutrals (black, navy, charcoal), two in lighter tones (white, sand, sage). Merino or technical cotton — they dry overnight if you sink-wash them.
• 2 button-up shirts. One short-sleeve linen for hot weather, one long-sleeve oxford for cool evenings and any time you need to look respectable.
• 2 pairs of pants. One darker, one lighter. Quick-dry fabric, but not so technical that you look like you are hiking the Appalachian Trail.
• 1 pair of shorts. Doubles as swimwear if you are not picky.
• 5 pairs of underwear, 5 pairs of socks. Yes, only five. You will be doing laundry. We will get to that.
• 1 light jacket. Even in summer. Air conditioning on buses and trains is brutal everywhere.
• 1 pair of versatile shoes you can walk 10 miles in, plus one pair of flip-flops or sandals.

That is it. Twelve to fifteen items. They all need to play nicely together — every piece should match every other piece. Pick a color palette and stick to it.

The technique

How you fold matters more than what you fold.

Roll your shirts, fold your pants. Rolling shirts saves space and reduces wrinkles. Pants are bulkier and roll into uneven sausages, so I fold them flat.

Use packing cubes. One cube for tops, one for bottoms, one for underwear and socks. Total cost: about thirty dollars. They turn your bag into a small dresser and keep things from migrating around.

Wear the heaviest items on the plane. Jacket, jeans, real shoes. This buys you space.

The laundry plan

The reason five pairs of underwear is enough is because you wash them.

• Sink wash every two or three days. Half a tablespoon of liquid soap, a sink full of cold water, ten minutes of scrubbing. Wring out, roll in a towel to remove water, hang on the back of a chair overnight.
• Laundromats once a week if you are in one place long enough. A wash and dry costs five to eight dollars in most countries.
• Hotel laundry is a trap. A single shirt at a four-star can cost twelve dollars to wash. Use this only when desperate.

What I do not pack

• Books. A Kindle weighs less than one paperback and holds two hundred.
• A second pair of dress shoes. Unless you have a wedding, you do not need them.
• Travel-sized everything. Most of the world has shampoo. Buy a small bottle when you arrive.
• A travel towel if you are staying in hotels. They have towels.
• A neck pillow. Personal preference, but I find them more useful as a punching bag than a sleep aid.
• Cash in multiple currencies. ATMs exist. Bring one debit card you trust, one credit card, and a backup of each.

What I always pack

• A small first-aid kit (band-aids, paracetamol, antihistamines, anti-diarrhea pills, hand sanitizer)
• A universal travel adapter and a 20,000 mAh power bank
• A reusable water bottle (saves you ten dollars a day in airport prices)
• A small notebook and a pen
• Earplugs and an eye mask

The math

A backpack at 40L, packed properly, weighs eight to ten kilograms. That is well under every carry-on limit, including the strict European low-cost airlines. You will not be charged at the gate. You will not check anything. You will walk off the plane and into the city.

The first time you do it, it feels precarious. By the second trip, you wonder why you ever carried more.

The trick, as with most things, is realizing you needed less than you thought.