How about the usage of mandatory constraints in a schedule. normally i use the mandatory constraints for a certain milestones and project finish dates. But, recently, had a dispute with my client regarding this. It is said that the mandatory constraint will reflect a wrong logic when the activities get delayed. instead they want me to use early / late constraints. but in case of early / late constraints the schedule will never be critical pushing the finsih date as the project gets delayed keeping the lag intact. but still i would like to get some ideas of you, experts about the usage of mandatory constraints.