How do I prevent my office chair from slowly sinking during the day?

A chair that gradually sinks has a gas cylinder with worn internal seals — this is a maintenance issue, not a user error. The fix is replacing the gas cylinder, which costs $20–$45 and takes about 10 minutes with a rubber mallet and pipe. A temporary workaround is a plastic cylinder stop ring ("chair saver ring") that slides over the cylinder and prevents it from compressing — a $5–$10 fix that buys time. Once a cylinder starts sinking, it will continue and should be replaced. FindOfficeFurniture.com sells long-lasting chairs with quality cylinders — call 888-719-4960.