This is actually based on a mash-up of two existing designs. But to answer your question directly, I try very hard to take durability into account. I already know that nylon parts can be very durable given enough material thickness. I don't always get it right the first time but I am learning just how thin and lightweight these parts can be while maintaining usability. On stuff I am not 100% on, I order copies for myself and test them often to destruction.

There are also plenty of YouTube videos showing the strength of 3D printed nylon parts. There are other people that use 3D printed parts for all sorts of mounts. There is a UK company that sells many more than I do.

I tend to design parts I need, then offer them to others. But I do get a few requests. If I can and I find the request interesting I try my best to come up with something. That is how this part came about. Someone asked about a combo Virb/Edge mount, I looked at my cheap chinese plastic out front Edge mount and thought about how I could adapt the design to add a Virb mount. Someone on another board suggested a mount that could rotate like the Garmin flat mount. I went and bought some genuine Garmin mounts and created this mash up. While I was designing it a thought came to me about why are all the out front mounts made for the right side of the handlebars, that's why there are two versions. I am just an enthusiast who dabbles in things like 3D printing and other cutting edge tech. It's an iterative process, if something isn't strong enough on the first go I redesign and try again. That said, I use the parts I design on a daily basis. I trust is with my stuff.