Updating and changes in data date

Typically that is what I do. One reason is if your are fairly on schedule the activities that you are applying actual dates to should be close to the forecasted dates that are there. If you change the data date by 1 month they will be off by at least 1 month. Its easier to pick an actual start and or finish date in the given month than to have to scroll backwards to the previous month EVERY time you want to recored an actual start or finish date. 

NO Actual dates can be after the data date and if you move the data date the early start and or finish dates will be forecasted in the next month so for ANY actuals you will have to scroll back a month.

As David said until ALL activities have been properly progressed the schedule is incorrect. Since this is a CMP schedule WITH LOGIC by not progressing one activity could impact another activity and give you a false dates. 

There generally isn't an issue with whether you press F9 in the middle of update or after actualizing all the activities.

Personally i press F9 after updating each task to see how the progress of said task impacts the schedule in its entirety. In this way I am able to easily spot out of sequence updates which may be erroneous or a result of a change in strategy / methodology. As long as all the tasks are updated as per the current status date or data date at the end of the day, there shouldn't be an issue.

The only concern here would be if you have resources loaded and the activity type involves the following types:

• Fixed Duration & Units / Time
• Fixed Units / Time

In such a circumstance, you would need to be wary of how your change of data date would impact the units allocated as a change in duration would result in a change in units.