Travelling carry-on only is a volume budget rather than a packing technique. A cabin bag is roughly 35 litres, and once you know what your trip generates against that number the decisions make themselves.
A cabin suitcase is roughly 35 litres, typically capped near 55 x 40 x 20 cm and about 7 kg, though airlines vary and the low-cost carriers vary most. Treat it as a budget: once you know what your trip generates against that number, the decisions stop being guesswork.
Generated by the packing tool for seven days in a mild climate.
For a week of mild-weather city travel the generator estimates ~15L packed (0L worn/carried) and it fits a carry-on: Carry-on.
Documents, tech and toiletries are close to a fixed cost — they barely change between a three-day trip and a fortnight. Clothing is the variable, and shoes are the worst offender per item.
Carry-on only saves time at the airport and removes the risk of a delayed bag. It is not a virtue in itself. Winter trips, trips with specialist gear, and any fare where a hold bag is cheap are all cases where checking is simply the better choice.
A typical cabin suitcase is around 35 litres with a limit near 55 x 40 x 20 cm and about 7 kg, though airlines differ. Most warm-weather trips of a week or two land well inside that; cold-weather trips are the ones that push against it.
Do laundry once. Beyond roughly a week, packing volume is decided by whether you plan to wash clothes, not by trip length — a fortnight with one laundry stop packs much like a week.
Containers of 100 ml or less in a single clear bag, at most airports. Solid alternatives such as bar shampoo sidestep the limit entirely if you are close to it.
Yes, if you are near the limit. A coat and boots worn rather than packed can be several litres, which is often the whole difference.
Winter trips, trips with specialist gear, and anything where the fare makes a checked bag cheap. Carry-on only is a means to save time and risk, not a rule worth suffering for.