Why do this on a timer? It can be a resource hog and continues to fire when the form is open and everyone is at lunch (if you get my point). Refresh the control on the form AfterInsert event and if you will restrict the counter update to newly added records. If the form is unbound, use whatever event saves the record. If the info (count) isn't current then it's not that vital - but that might be OK for the process. Besides, it's far less code than writing a timer event for this, not to mention that when Boss says "I want it every 5 minutes" you're not going into form design or table data and changing the timer interval.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.