database sharding, when should you actually do it. It isnt always the answer, you know.

hey folks, i'm wrestling with scaling a rapidly growing application and the idea of database sharding keeps coming up. we're hitting some performance bottlenecks with our single large postgresql instance. i've read the theory, but i'm curious about real-world experiences. when did you decide sharding was the right path, and what were the biggest headaches you encountered during implementation and ongoing maintenance? are there alternatives you explored first that worked just as well or better?