Or commands enable you to select from a list of alternate resources. Each time a schedule is run there is a chance that a different resource will be selected then what was selected on the previous schedule run. You can optionally “stabilize” the scheduled selection by imposing a time fence. If for example, your time fence was 7 days and the operation with the Or command fell within 7 days of the schedule run date, the resource selected would lock and not allow a different resource to be selected on any future schedule runs.  The Or Time Fence is set in the schedule options.