One-bag travel is a habit more than a product. The bag sets the ceiling; the method decides whether you hit it. This is the sequence we use, written so it works with any suitcase-style backpack and any packing cubes.
Start with the shoe rule
Wear the bulkiest pair; pack at most one more. Shoes are the item that most often pushes a 28 litre bag into "needs a second bag" territory, and a laundry/shoe bag keeps the packed pair away from clothes.
Plan outfits by day, then subtract
Lay out seven days of clothing, then remove anything that only works with one other item. Three bottoms, five or six tops and two layers cover a week with one mid-trip wash. Choose fabrics that dry overnight if you plan to wash in a sink.
Cubes by category, not by day
One large cube for tops and bottoms, one small cube for underwear and socks, one small cube or pouch for chargers and cables. Compression cubes have a second zipper that squeezes the contents flat once closed; use it on soft clothing, not on anything you want to keep crease-free. Note the cube's listed dimensions against the bag's main compartment before you buy; our guide lists the sizes.
Heavy at the back, flat against the spine
In a backpack that opens flat like a suitcase, the laptop sleeve and the heaviest cube go against the back panel. Lighter cubes stack toward the lid. Shoes go in the bottom corners, soles out.
Toiletries: travel sizes, one bag, liquids rule checked
A hanging toiletry bag with bottle bands keeps liquids upright. It is an organizer, not a substitute for the clear liquids container many airports require at security; check the current rule for your route.
The last 10 percent stays empty
Leave room for the thing you buy on day three. A bag packed to the zipper on departure is a bag that does not close on the way home.
The One-Bag Travel route lists the bags and cubes in our range that suit this method. Sizes and weights there are the makers' listed figures.