What if I need something I didn't pack?

Every city in the world has shops. If you truly need an item that wasn't in your original pack, buy it locally. You will almost certainly find it cheaper or better suited to the climate.

Are packing cubes actually worth the space?

Yes. They don't save space, but they keep your bag organized so you don't have to dump your entire life out to find a pair of socks.

How to travel indefinitely with only a carry-on

Limit your luggage to a single 35-40 liter backpack and commit to doing laundry once a week. If you can't carry everything you own comfortably for 15 minutes, you have packed too much.

Select the right bag. Purchase a high-quality, frameless 35-40 liter travel backpack. Ensure it meets standard international carry-on dimensions (roughly 22 x 14 x 9 inches) to avoid gate-checking fees and stress.
Apply the 5-4-3-2-1 rule. Pack no more than 5 pairs of socks and underwear, 4 shirts, 3 bottoms (including the one you wear), 2 pairs of shoes, and 1 jacket. Anything else is a luxury you don't need.
Use a capsule wardrobe. Stick to a single color palette (e.g., navy, grey, and black). Every top must match every bottom so you can create multiple outfits from a small selection of clothes.
Master the laundry cycle. Carry a universal sink stopper and a travel-sized tube of concentrated laundry detergent. Wash small items in the sink every 3-4 days to prevent clothes from piling up.
Digitize everything. Do not pack physical books, maps, or notebooks. Use your phone or a single e-reader for all entertainment and research to save at least 2 kilograms of weight.

What if I need something I didn't pack?: Every city in the world has shops. If you truly need an item that wasn't in your original pack, buy it locally. You will almost certainly find it cheaper or better suited to the climate.
Are packing cubes actually worth the space?: Yes. They don't save space, but they keep your bag organized so you don't have to dump your entire life out to find a pair of socks.