Reinforcing Backpacks and Bags + Making Shoulder Straps

Dear users, dear authors,
Do you have any tips for reinforcing backpacks and bags? How can you make durable shoulder straps?

I’ve used foam rubber for small bags before.

If you want thinner fabrics to hang freely, non-woven interfacing helps.
For the shoulder straps, there’s ready-made webbing available in many colors and widths—you can usually find something that works. That said, I’ve come to prefer chains for very thin straps.