I started my trip with a 70L bag that weighed 18kg. I ended it with a 40L bag that weighed 7kg. The downsizing happened because I kept jettisoning things that weren't earning their weight — and eventually figured out what actually mattered.
The Bag: Osprey Farpoint 40
Fits all major airline carry-on requirements. Hip belt for distribution on hiking days. Lockable zippers. Harness hides away for checking when airlines force it. The clamshell opening makes packing and security checks civilized. After 14 months: zero failures. Zero repairs. One cosmetic scuff on the zipper pull. This bag will outlive me.
Packing Cubes: Not Optional
Eagle Creek Specter cubes compress properly and the ultra-light versions don't add meaningless weight. Compression cubes from Amazon generic brands degrade in 3-4 months. Buy Eagle Creek once, use forever. The system: one cube for tops, one for bottoms, one for electronics, one for toiletries pouch. Instant packing, instant unpacking at customs.
Power: The GaN Charger Eliminated 3 Cables
An Anker 65W GaN charger with two USB-C and one USB-A replaced my laptop brick, phone charger, and headphone charger. One item, three devices, 65W. Combined with a universal adapter (the EU/UK/AU/US combination ones are $15 and they work), I have one power item total.
Security: Two Locks
TSA-approved combination lock for luggage (airports only — a determined thief gets past these in 30 seconds, but that's not what they're for). Pacsafe cable lock for hostel lockers and daytime café laptop security. The cable goes through my bag strap and around a fixed object. Theft prevention is about making yourself a harder target than the next person.