Over the past few years, the shape of glasses that I prefer has been getting harder to find. Last year, all major manufacturers stopped making them altogether. I tried a new frame that I didn't really like (it was sort of the right shape, but tilted up a bit at the outer corners, which kept making me think of cat-eye glasses even though the tilt was fairly subtle), but I ended up just getting new lenses put into my old frame.
But my old frame is showing signs of wear around the temples, so I resigned myself to getting a new one that I wasn't going to like. And I went in to the optometrist yesterday (Dr. Kuo is great; I always enjoy my appointments with her), and she told me that suddenly my preferred frame shape is in style. Not only is it being made again, but it's in high demand; she thought they might even be sold out. And I ended up getting new ones that are almost exactly the same shape as my old ones.
Apparently it's true that if you wait long enough, the old-fashioned stuff comes back into style.