Online health communities are places where people can come together in order to exchange social support at a particular point in an individual's life. There are, however, relatively few accounts that look across multiple communities across the lifespan. In this paper, we reflect on four case studies of research on different online health communities in order to identify patterns in how individuals selectively adopt, use, and disengage from these communities throughout their lives. We argue that users leaving communities is not necessarily a failing of the site's design or purpose; rather, it is a logical reaction to changing life circumstances. In characterizing this pattern, we contribute a set of implications for design and management that bear consideration by online community designers, developers, moderators, and end users. Ultimately this may lead to a smoother transition from community to community and ensure that social support needs are being met more consistently in response to changing life circumstances.