The topic of availability management has been extensively investigated in related research. However, thus far the approach to this subject was primarily motivated by the need to protect an interruptee from an unwanted interruption. In this approach, availability status was assumed to be static: either the interruptee was interactive, thus willing to accept an interruption or interpassive, thus prone to reject it. In this research we would like to propose a different assumption: that availability status has a dynamic rather than a static nature and that both communicators conjointly influence that status. To test that assumption, we explored the nature of availability and factors that are likely to influence it through a series of empirical investigations. These studies have shown that availability state is likely to be influenced by factors such as: social proximity, nature of the communication subject and anticipated interruption duration. We have also observed that while social proximity was shown to be a crucial factor for face-to-face communications, it appeared to have little impact on the availability status in email communications.