When should you think about putting your app in more than one region

Hey everyone, I'm trying to figure out when we should make our app multi-region. We're doing okay with uptime in just one spot, but we're seeing more and more users popping up on different continents. Other than disaster recovery and cutting down on lag for people far away, what else makes you decide to go multi-region? Are there certain traffic trends, rules we have to follow, or parts of our setup that make it an obvious yes, or a clear no? Would love to hear what you guys have gone through.