Currently, I'm using (Month(NOW()) to set the current month number in cell $D$1 of a spreadsheet. I know Month and Now are volatile functions and they're making the over sheet update way too slowly, so what I thought I'd do is try to set the value of that cell just once a day through a script. I'm not at all familiar with writing Google Sheet scripts or calling them from a cell, and certainly not setting them to run at a given time. Any specific guidance would be appreciated. To be clear, the result of the script should be a simple number, one through twelve, identifying the current month number, and the associated cell should only be updated once a day.