The present invention relates to a system and method to facilitate communications of important messages, communications, or interactions. Policies are introduced that consider a user's current situation, including the cost of interrupting the user, or directly sensed surrogates for such a cost, and decide on a suitable time, within a deadline for delivering the information or establishing a communication. Deadlines for delivery are determined based on the urgency of the information that is inferred or detected from the message sender, type, and content. If a suitable context is not detected within a deadline, the information is delivered at the deadline. If it is determined that a suitable context will not achieved within a deadline, the information is transmitted immediately. Suitable contexts for delivery can be determined via the use of one or more sensors on or near endpoint devices, including accelerometers, microphones, touch sensing, and gaze and head pose detection. Other information, including appointment status as indicated on a user's calendar, the time of day, and previously assessed patterns of availability can be employed in decisions about the deferral of alerts. Endpoint sensors, calendar information, and patterns of availability also may used to identify the likelihood that information will be received at a device. Such information can be passed back directly or in a summary form as the likelihood of transmission success to a central notification manager or used locally in decisions about the salience and repetition of alerting.