For partner systems that tend to respond slowly, Exchange users may develop the habit of querying twice for other users' free and busy information. Exchange users may initiate a query knowing that it will likely time out, then wait a few minutes and query again to get the latest data. This works because free and busy data is still written to a free and busy record in the public folder store, even if a client times out while waiting for it. When Exchange users make a second free and busy query while that information is still current, they can still receive the late-arriving information.
Related TopicsFree and Busy Calendaring Overview Communicating with Partner Systems Understanding the Status of Free and Busy Information Implementation Considerations