You could set up a table with a date field set to the last time the script ran. Have the on open script check the date field against current date and run the script if it has been the desired length of time. As part of the script update the date field.
This assumes the file is opened and closed on a daily basis. So that the On Open script is run.
You could also attach a script trigger that runs when a specific layout is opened. Have it set a global variable to show that it has been run so that it exits after the first run.