Keep track of when form data has changed

[TimTDP]

I want to keep track of when data in a form was last changed.
I only need to track this when the form is closed. not every time a record is changed.

What event should I use?

 

[TimTDP]

If a user opens the form and does nothing, then I am not interested

However if the user changes any data, than I only to know this when the form closes.

 

[vbaInet]

If a user opens the form and does nothing, then I am not interested

The user could still open the form, change data but revert it to it's old state, however the form's After Update event will still fire. So when coding for this you'll need to bear that in mind. That's why Uncle Gizmo has mentioned comparing each control's old value against the new value. But you only do this before the update otherwise they'll be no old value.
And you can save a list of the records that were changed (if users are allowed to make multiple record changes).

We'll wait for more information as requested.