Would you like to act upon specific spreadsheet-changes? Then install this addon, and let it watch specific columns. Or, even better: create a formula which triggers a notification. All this can be done without programming-knowledge. Reactor is your secret weapon to reduce your workload. It detects changes in spreadsheets, and acts upon them (email etc). Start building flexible rules now, to automate reports, notifications and management tasks. An Example: Multiple collegues are working in the same sheet. Bill updates the inventory in cell A10. However, if the inventory is below 5, then Mitchell should increase the purchase order. We'll create a rule: IF( A10 < 5, TRUE, FALSE ) Done. From now on, mitchell will receive an email when it's below 5.