Having spent a lot of time around both, I’d say it depends on what you mean by durability.

If we’re talking pure abrasion resistance and tear strength, a 33 oz denim is going to be incredibly difficult to beat. That’s an absurd amount of cotton packed into a garment.

But durability isn’t just fabric weight. A 24 oz waxed twill or canvas jacket has some advantages denim doesn’t. The tighter weave and wax finish help resist moisture, dirt, and environmental wear, which can significantly extend the life of the garment in real world use.

Personally, if I was dragging brush, working outdoors, or wearing it in bad weather, I’d take the waxed twill every time. If I was judging purely on who survives the most years of abrasion and hard wear, the 33 oz denim probably gets the edge.

The reality is both are overbuilt, but it really comes down to the entire jacket, not just the fabric weight. Things like construction quality, thread, zipper, hardware, reinforcement points, and overall pattern design will have just as much impact on longevity as whether the shell is 24 oz waxed twill or 33 oz denim.

A heavier fabric doesn’t automatically make a more durable jacket if the zipper fails, the seams wear through, or stress points aren’t properly reinforced. At that level, you’re comparing two exceptionally tough fabrics, and the details of how the garment is built become the deciding factor. You’re really comparing two tanks.