1. The "fixed" value, whether it be Units, Work, or Duration, is the value that you do not want Microsoft Project to recalculate for you in the Duration Equation.

Thus, on a Fixed Work task, if you change the Units then the Duration is recalculated, and if you change the Duration then the Units are recalculated, but the software won't recalculate the Work for you because that value is fixed.

You should set the "fixed" variable on a task by task basis, based on the requirements of the task. For example, if a task has a "window of opportunity" of 5 days to complete work on the task, and the window will not change, then I would say that is a Fixed Duration task with a Duration of 5 days.

2. You will need to supply two of the three values in the Duration equation on each task and assignment. These values are Duration, Work, and Units. In some situations, it is most helpful to enter a Units value and a Work value for each resource assigned to a task, and then let the software calculate the Duration of that task for you.

In other cases, you may need to set a Duration and then enter either a Work or Units value. It's all based on your scheduling needs. The Task Type also comes into play as well when you set assignments.

Yes, you are correct that you should not enter a Start or Finish date for any task, as this automatically sets a constraint on the task. If you need to set a constraint on a task, then double click the task, select the Advanced tab, manually set the constraint there, and then add a task Note to document why you set the constraint.

A Priority number can be set at both the project level and the task level, and you are correct that it is used only in leveling.

3. The software is behaving as it is meant to work. If you have a Fixed Units task, and then you attempt to adjust both the Duration and the Work, the software WILL NOT recalculate the Units value for you. Why? Because the Units are fixed.

If you have a Fixed Work task, you should adjust the Work value first, and then let the software recaluclate the Duration, which is its default behavior. Then adjust the Duration and the software will recalculate the Units for you.

You can fix or "lock" one of the three values in the Duration equation, which are Duration, Work, or Units. This is known as the Task Type setting for each task, and the Task Type can be either Fixed Units, Fixed Work, or Fixed Duration.

By default, the Task Type for each task is Fixed Units, which explains the behavior you are seeing. When Units are fixed and you change Duration, Work is recalculated automatically, and if you change Work then Duration is recalculated. To fix either the Duration of Work values for a single task, do the following:

1. Double-click the task in question
2. Click the Advanced tab
3. Set the Task Type value to either Fixed Work or Fixed Duration
4. Click OK

To set the Task Type for every task in a project, click the Select All button in the upper left corner of the task sheet (blank gray button) to select all tasks in the project.

Click the Task Information button in the middle of the Standard toolbar, and then complete steps 2-4 above. To set the default Task Type for every task in every new project, do the following:

Another way of protecting your original Work and Duration values, as well as the Start date and Finish date for each task is to baseline your project before you begin entering progress.

To do so, click Tools - Tracking - Save Baseline and then click OK. The Baseline Duration, Baseline Work, Baseline Start, and Baseline Finish values will reflect your original starting values on each task, summary task, and for the project as a whole. As long as you don't rebaseline the project, these values will not change. Hope this explanation helps.