The problem with travel bags is that trips aren't all the same size
You buy a bag for the two-week trip and then carry it, mostly empty and flopping about, on the overnight one. Or you buy for the overnight and end up sitting on the zip in a hotel room. Neither is a good outcome, and most people solve it by owning three bags they each use twice a year.
The MATEIN's answer is a proper expandable design. Zip it closed and it's a compact carry-on shape. Open the expansion and you've got 40L for the longer trip. External compression straps then pull the load in tight either way, so a half-packed bag doesn't slosh around on your back. That's one bag doing two jobs, and for occasional travellers it's genuinely the most sensible way to spend the money.
Packing is straightforward. It opens lay-flat like a suitcase, so you can arrange things in layers and see the lot. Separate laptop storage keeps your machine out of the general shuffle and easy to pull at security. Multiple organizer pockets give cables, chargers and toiletries fixed homes ā which matters more on the return leg, when nobody repacks as carefully as they did the first time.
There's a hidden anti-theft pocket against the back panel for the passport and cards, and a luggage-handle strap so it rides your suitcase through the terminal rather than your shoulders. Water-resistant fabric handles a taxi rank in the rain. The padded shoulder harness is comfortable for the distances a traveller actually walks ā terminals, platforms, the fifteen minutes from a station to a hotel.
Set expectations sensibly: this is a value bag, not an expedition pack, and the harness reflects that if you load it to the limit and walk for an hour. But for the way most people travel, that's not the trip. If you're heading somewhere in the next few months and you've been putting off replacing the bag with the failing zip ā this is the practical, inexpensive, obviously-correct move. Have a look.
