jr377, I would have to disagree drawing from experience. There have been people who are on a project with me doing a certain task who, for various different reasons, get transferred to another project. The reason for this often has been due to people leaving the company, higher priority projects needing more of the departments resources, etc. To mitigate this, ideally (like you said) there would be other people who are doing the same tasks who would either fill in for the gap or train a new employee who would take over the task. Another way to mitigate this is have the leaving employee train the incoming employee (if there are no reduntant employees doing the task). This of course does not really protect against sudden changes where people drop from the project due to leaving, but it is at least a measure to take.