Cut+Dry Ideas

Could you add an additional customization ability to the IF statements for alerts, ideally custom time amounts, possibly from a drop down, consisting from 1-7 or 1-30 for the days not ordered. I have customers who order more than once a week and would like to do a setup that reminds them every 2-3 days of not ordering, and not the every day option, where they would start to ignore the messages.