Don't miss these other scheduling options: setting a delay date and putting an item on hold

Promise by

If you have a date by which something must be completed, you can set a “promise by” date via the scheduling tab in the edit pane.  

The “promise by” date is shown in the schedule view as a black diamond.  When a promise date is set on a container, all items in that container inherit that promise date as shown by the gray diamonds:

It is best practice to put your promise dates on containers - task lists or projects.  Promise dates are not meant to be used as intended finish dates on every task.  Remember, LiquidPlanner will calculate for you a range of likely finish dates based on the ranged estimates and priority order of your tasks.

At-risk alerts

A promise date will trigger an alert when you are at risk of not meeting that promise date.  In the scenario below, two additional tasks have been added to the Phase I task list.  The last task is putting Phase I at risk because it won't be done before the promise date.  In addition to the red schedule bars, you are also alerted via the red flame icons in the left margin.  Clicking on those icons will give you a written description of the risk.