[AccessD] How to update the Changed field in a table

This may be a good use of class modules.

 

I have bound controls on a form which is bound to a table.

 

I was hoping to have some sort of form level validation, as opposed to field
level validation, but it seems that when a form is on a record, that any
change made in a field is causing a change in that field. and there is no
resetting back to its old value based on field level validation or
confirmation - unlike unbound controls, which I can let anything the user
does to them occur until ready to save the record?

 

I want particularly, not to stamped the changed date with each and every
edit, but to 

1)      Only stamp the record if the user saves or exits the form

2)      Only stamp it once

 

Admittedly I have NEVER used bound controls, and maybe some of this behavior
is already inherent in Access.

 

Can someone tell me what they customarily do in this need?