A duffel has no frame, so almost everything about how long it lasts is decided by construction you cannot see in a photograph. These four checks cover it.

Turn it upside down first

If the handle webbing runs under the base and up the other side as one continuous length, the strap carries the load and the body fabric carries nothing.

If the webbing stops where it is stitched to the side, every kilo in the bag is trying to pull four small patches of fabric off it. The webbing will not break; the fabric will tear around it, all at once, when the bag is fullest.

Ask what the base is

A duffel is put down constantly, so the base wears from the outside while the rest of the bag is barely used.

You want a separate reinforced base panel, and you want the seam joining it lifted up the side rather than run around the bottom edge — otherwise the stitching is dragged along the ground every time the bag is moved.

Get three dimensions, not litres

Two bags at the same litres can be entirely different shapes, and shape is what decides whether a bag fits a locker, a shelf or a boot.

Length, width, height and a description of the shape. Any supplier who has measured their own bag can give you all four.

Be precise about waterproof

Coating the fabric does nothing about the zip, which is a row of gaps, or the seams, which are thousands of needle holes.

Genuinely waterproof means welded seams and a roll-top closure. Everything else is water-resistant, and a supplier who blurs that line is telling you something about the rest of the quote.

Then, and only then, talk about fabric

Higher denier resists abrasion, which matters at the base and on the corners.

It does very little at the anchor points, because that failure is fabric being pulled apart rather than worn through. Fix the load path first.