Currently the Android implementation of SimplyE caches indefinitely the information it receives from authentication documents. This information does change occasionally, changes can be significant, and authentication documents are cheap to serve, so it's better to refresh this information periodically.

Until we come up with a more comprehensive solution, cache this information for no longer than one hour. If the authentication document is not available (e.g. the server is down), it's fine to reuse old information until the document can be refreshed.