I use a "Save Record" Button but you could probably trigger it on any event. here is a sample of the code I used.
' prompt for confirmation
Dim Msg, Style, Title, Response
Msg = "Save and Close Record Now?" ' Define message.
Style = vbYesNo + vbQuestion + vbDefaultButton1 ' Define buttons.
Title = "SAVE RECORD?" ' Define title.
' Display message.
Response = MsgBox(Msg, Style, Title)
If Response = vbYes Then
' Save all values on form
Dim db As Database
Dim rs As Recordset
Set db = CurrentDb
Set rs = db.OpenRecordset("tablename", DB_OPEN_DYNASET)
rs.AddNew
rs!field1 = Me!control1
rs!field2 = Me!control2
rs!field3 = Me!control3
rs!field4 = Date
rs.Update
End If
Hope this helps