In this issue of Photonics Focus, we examine cycles as they relate to re-using glass, monitoring sunspots, and tracking nutrient flow in the world's oceans. One feature surveys the efforts of optics glassmakers to sustainably manufacture and recycle glass. A second feature reveals how researchers track sunspot cycles—critical understanding needed to protect the world's electronics infrastructure. Finally, a third feature looks at optics technologies being deployed as ocean sentinels to shed light on biogeochemical cycling in some of the most remote areas of the planet.