After you complete a schedule, you can view how many hours each volunteer was scheduled by running a report from the schedule window.  Click on the Reports menu at the top of the scheduling window, and select "View Hours Scheduled..."

A new dialog will open that will list all of your volunteers in the first column, and all of your jobs along the top.  By clicking on a job heading, you can reorganize the report to show those who were scheduled for that job in descending order.

If you feel like any volunteer was scheduled too often or not enough, you can right click on their name or their hours to add or remove assignments.  This report can also be exported to a spreadsheet by clicking the "Export..." button in the lower right hand side of the window.