When I worked as an instructor at BCIT, I got a free pair every two years through my insurance. Since retirement, I have been buying new pairs when we're travelling to a country where they're cheaper. In fact, the ones I'm replacing were purchased in Kuala Lumpur.
I've broken more frames than I care to count. More importantly, polycarbonate plastic lenses may be lighter than glass, but even with expensive 'special coatings', they never last a very long time. Over time, minute scratches make looking through them hazy.
This morning, I ordered two pairs with my old prescription through Zenni® online. The price looked astonishingly lower than retail shops. I remember a previous, poor experience years ago with a business called, Clearly Contacts. We'll see if today's decision pays off in the long run.