I once weighed my bag before a ten-day trip and again after I got home, having worn maybe a third of what I packed. It left at 14 kilograms and came back at 13.6 — the only real change being that I’d hauled all 14 up four flights of stairs, twice, for no reason at all.
Overpacking isn’t a character flaw. It’s a forecasting error — you insure yourself against every version of a trip that won’t happen, and the premium is paid in baggage fees, sore shoulders, and the tax of dragging a too-big bag through places that weren’t built for it. Here are the six mistakes I see most often, what each one costs, and the fix that reliably cuts the load. None of it requires buying anything.
1. Packing for the weather you fear, not the weather you’ll get
The classic mistake. You check the forecast, see a low of 9°C on one of seven days, and pack for that single cold morning — fleece, heavy jacket, the lot. The other six days sit between 18 and 24, and the cold-weather kit rides along as ballast.
The cost is volume. A jacket and a fleece together eat 8 to 10 litres and add a kilo and a half — often the difference between a bag that fits the sizer and one that doesn’t, which on a budget carrier is a gate fee for clothes you’ll wear once.
Pack one warm layer that stacks. A merino base plus a light packable shell handles 9°C as well as a fleece-and-jacket combo at a third of the weight — and you wear the bulky item on the plane, where it’s free.
2. The “just in case” pile nobody audits
Every overpacked bag contains a shadow bag: the items added in the last twenty minutes because you might need them. A second pair of shoes for the dinner that isn’t booked. A swimsuit for a coast you’re not visiting. Three “options” for one evening out.
I started tracking this a few years ago, and the pattern is depressingly consistent — I use roughly half of what I pack, and the just-in-case pile is almost entirely that unused half. The cost isn’t only weight; it’s decision friction, because a bag with twice the clothes you need is one you spend twice as long rummaging through at 6 a.m. in a dark dorm. It’s worth studying the kit one minimalist carried for a full year on the road, where every item earned its place by being used weekly.
Lay everything out. For each item ask: will I use this in a normal week of this trip? Not “could I” — will I. If the answer is no, it stays home. Most bags lose 20 to 30 percent of their volume on the spot.
3. Treating toiletries like you’re moving house
Full-size everything. A 400 ml shampoo for a four-day trip, the shower gel, the backup deodorant, the first-aid kit built for a small expedition. Liquids are dense — water doesn’t compress — so this is where weight hides, and where airport security turns your morning into a queue.
A full toiletry bag can run 1.5 to 2 kilograms, most of it product you’ll never finish. The fix is dull and effective: decant into 50–100 ml bottles, take only what you’ll use, and accept that shops exist at your destination — a bar of soap alone replaces three bottles. Liquids are usually what tips the scale, so this is also half the battle in staying inside a budget airline’s cabin-bag limit without checking anything.
4. Packing clothes that only do one job
This is the subtle one. You can pack light by item count and still pack badly, because every piece is single-purpose: the hiking trousers that only work for hiking, the going-out top that pairs with nothing. A wardrobe of specialists, each waiting for its one moment.
The cost is a poor ratio of outfits to volume: ten single-purpose items give you ten combinations, where ten coordinated ones in a tight palette give you thirty or forty.
Pick a base palette — navy, grey, black — and make every top work with every bottom. Add one item that dresses an outfit up. Three bottoms and four tops then cover a fortnight without anyone noticing you’re rotating.
5. Buying a bigger bag to “be comfortable”
Parkinson’s Law applies to luggage with grim reliability: a bag expands to fill the space available. Buy a 65-litre pack because the 40-litre one felt restrictive, and you will fill all 65. The empty space isn’t a buffer — it’s an invitation.
The bigger bag costs you twice — once in space and weight, and once more quietly: a 65-litre pack usually can’t be a carry-on, so you’ve committed to checked-bag fees and lost-luggage roulette.
The fix is to let the bag enforce the discipline you won’t. A 40-litre cap is uncomfortable enough that you make real choices, and small enough to stay in the cabin on most airlines — the limit decides for you, which is the point. That same carry-on-only minimalism is what makes risky-on-paper moves like hidden-city ticketing’s no-checked-bag requirement even thinkable: if it doesn’t fit in the cabin, the plan doesn’t work.
6. Packing the things, then forgetting you can do laundry
The final mistake is mathematical. People pack one outfit per day because they treat clean clothes as a fixed, non-renewable resource: fourteen days, fourteen of everything. The bag gets sized to a number that has nothing to do with how clothes work.
The cost is the worst kind, because it’s so avoidable. You carry ten extra shirts to dodge one twenty-minute sink wash or a laundromat run that costs a few coins — and since clothing is the bulkiest category in most bags, this mistake roughly doubles it.
Pack for five to seven days regardless of trip length, then wash. A merino top dries overnight; quick-dry synthetics are faster still. For a two-week trip this halves your clothing — usually the biggest line item in the bag.
What this looks like in numbers
The same two-week trip, packed two ways. The figures are illustrative, but the direction — eight kilograms saved without losing anything you’d use in a normal week — is the point.
| Category | Overpacked | Fixed |
|---|---|---|
| Clothing (days packed) | 14 of everything | 6 + laundry |
| Shoes | 3 pairs | 1 worn + 1 packed |
| Toiletries | ~1.8 kg, full-size | ~0.5 kg, decanted |
| Outerwear | Fleece + heavy jacket | Base layer + packable shell |
| Bag size | 65 L, checked | 40 L, cabin |
| Rough total weight | ~16 kg | ~8 kg |
Layer instead of duplicating. Audit the just-in-case pile against a one-week test. Decant your liquids. Build a capsule, not a collection of specialists. Cap the bag at 40 litres. And pack for a week, not a fortnight — laundry is the cheat code that halves the bag’s biggest category.
How light should a carry-on for two weeks actually be?
Aim for under 8 kilograms packed if you can. That keeps you inside the weight limit of even the stricter budget airlines and, more to the point, keeps the bag genuinely comfortable to carry up stairs and onto trains. Below 7 kg you stop noticing it’s there.
Won’t doing laundry on the road eat into my holiday?
Less than you’d think. A sink wash is twenty mostly hands-off minutes; a laundromat run is an hour you can spend reading or eating nearby. Set against the time and money lost dragging a checked bag through every transfer for two weeks, the maths favours laundry comfortably.
What’s the single most effective change if I make only one?
Cap your bag size. Use nothing larger than 40 litres and the constraint does the editing for you — you physically cannot pack the just-in-case pile if it won’t fit. Every other fix gets easier once the container is the right size.
Pack a bag this week for a trip you’re not even taking, just to see what your defaults are. The unused half is easy to spot once it’s lying on the bed instead of zipped out of sight — leave it there, and your shoulders, your wallet, and every flight of stairs will thank you.
