I'm a high rise window cleaner who does rappel work every day. I bought these sunglasses because I needed durable, polarized shades that looked good and stayed on my face, and the lifetime warranty sold me. Of course, I still try my best to take care of them, but accidents happen. One day when I was leaning over a wall, they fell off my shirt six stories, landed on a glass sub-roof (see picture), and slid. When I retrieved them later in the day, the lenses had stayed in, and not even a scratch or bend.
That's not to say they can't get damaged. I'm receiving my third pair soon. I stepped on the first pair and the left hinge broke off. The second pair's hinge connector got bent and eventually sheared off. But, I tend not to put them away as I should, and a very thin piece of titanium can only hold up to so much.
The only downside in my eyes is that the plastic lenses could be a lot more scratch-proof. Over time, they get swirl mark scratches, and larger scratches are also fairly easy to get, even being careful. You can step on them once without breaking them, but not without consequences. Super awesome glasses all around, 10/10 would recommend.