What actually fits in a 25, 30 and 45 litre duffle

Litres do not mean much until you fill them

The shoe compartment is the point

Every duffle in this section puts the shoes in their own ventilated end, separated from the main body by a fabric wall. This is the whole argument for a gym duffle over any other holdall. Shoes carry grit, damp and smell, and none of it reaches your clean shirt. The compartment takes up to about a US men's 12 on the 30 litre bag.

The wet pocket at the other end

A second sealed pocket sits opposite the shoes for a wet towel or swim kit. It is lined rather than waterproof, so it will hold damp for an hour or two on the way home. It is not a place to leave a soaking towel overnight, and the bag will smell if you do.

How to load one so it carries well

• Heavy items along the base and close to the back panel. A duffle loaded at the far end swings and pulls on one shoulder.
• Towel rolled along the length rather than folded, which uses the dead space at the top of the main body.
• Bottle upright in a side pocket, not lying in the main compartment. Every duffle here has one.
• Laptop, if the model takes one, in its sleeve against the back panel and nothing hard behind it.

Cleaning

Empty it completely, including the shoe end, and leave both zips open overnight once a week. Wipe the inside with a damp cloth and a drop of washing-up liquid when it needs it. Machine washing polyester duffles breaks down the coating on the base and the stiffener in the panels, so do not.