You can establish a vacancy and collection loss factor for each year.  Remember that this number is for unanticipated credit losses, and unanticipated vacancy terms.  Later in the model, you will be entering projected down time for each lease by using the Turnover Tool.  Use this entry to specify anticipated Vacancy and credit loss above and beyond that which you build into the model when you set up the individual leases.  If you do not plan to enter individual leases and instead use the income estimator, make sure that your entry here is sufficient to cover both vacancy and credit losses.  To learn more about using the turnover tool, see Lease Turnover Tool