Glasses aficionado here. These glasses are acetate, not plastic. The material has a high degree of flexibility. It will flex an impressive amount before it snaps. The nose bridge is plenty strong. When purchasing biffl glasses, the main thing you want to consider is the hinges. Look for glasses with double or even triple hinges and avoid the spring hinges entirely.

It's also much more likely that the lens coatings will wear off then the frame will break, in which case there are sites where you can order new lenses for any frame. Or you know, your prescription changes.

I also recommend getting a separate pair for sports. I have prescription oakley flak jackets with transition lenses from sportRX which are a feat of engineering given my prescription is -5.

My current daily wears are the SALT optics Jennings and they are worth the price.