Years ago I had a tote bag similar to this. It was smaller, but for me it was the most practical bag I owned, and literally wore it out. Purl Soho designed a very sturdy one using heel stitch, which you may be familiar with because sock heels are often made with this slip stitch pattern. They used Lantern yarn, a blend of cotton and linen, a great choice for a hand knit bag. I also love the marled effect of this yarn, which adds texture. What I might suggest is to line the bag for even more durability, but also to prevent items from poking through.