The lost-bag risk you skip is real. Airlines mishandled 33.4 million bags in 2024, one in 159, and five times that on international routes with a hub transfer ¹. Most come back within two days, no help when you land for a five-day trip with nothing to wear.

The time is the bigger prize. Skipping the carousel saves fifteen to forty-five minutes per flight, more at big hubs ². With the bag-drop queue, that's most of an hour you never spend. US passengers also paid $6.8 billion in bag fees in 2022, first-bag fees now $40–$55 ³.

Five shirts covering three weeks isn't a trick, it's the fabric. Merino traps odour compounds inside the fibre, not on the surface where skin bacteria feed, so it needs laundering far less than cotton ⁴. In a five-day trial, 85% called the polyester layer unwearable by day seven while merino was still fine ⁵; socks too ⁶.

The airline rules set the ceiling. US majors allow 22×14×9 in with no domestic weight limit, but most international carriers strictly enforce 7–10 kg ⁷. Keep the setup near seven kilos and it works anywhere; that's also the healthy load for a seventy-kilo adult, a tenth of body weight ⁸. The gear runs $600 to $1,500 the first year, but merino lasts three to seven years to cotton's one.

The first trip is the one that converts you. You clear the airport in ten minutes and you're on the train while your seatmate is still at customs. Within a few months you stop dreading short trips: a weekend away is worth it for one good dinner, because the overhead has roughly halved. The change lands within three or four trips.

Check a bag for young kids, specialised gear, or multi-climate trips. Carry-on plus a personal item doubles the volume and keeps the airport speed. Door-to-door shipping ($50–$200 a leg) suits skiers and golfers.