I’ve been very fortunate in that my optical prescription has been nearly unchanging for the last several years. I’m also fortunate in that my prescription is straightforward enough that I can buy glasses from overseas sellers. Mrs. Magnet has a very challenging prescription and the one time I bought her a spare pair of glasses from the place I get mine they were completely unusable. Similarly, I’m fortunate in that contact lenses work well for me for 14+ hours a day.
The end result is that I wear contact lenses an average of 364 days a year, but that I keep a pair of glasses next to my bed, in my laptop bag, and in my car’s emergency kit. All in this was WAY less than a pair of Mrs. Magnet’s glasses. They were far more expensive but I also invested in a pair of prescription inserts for my eyepro (ESS ICE).
When my prescription next changes significantly, I’ll buy a pair online and try them out before replacing the others.
My one glasses day this year (so far) came from something as simple as a contact lens going AWOL on a day trip last week. It’s very unusual for me but it did happen.
Every so often I see ads for the dial-adjustable glasses and think that they would be great to have around for an emergency, and then I read the reviews and don’t buy any. If anyone here has first-hand experience with them, I’d love to know.