If you want to be reminded at regular intervals that you’re not timing tasks, navigate to the Grindstone menu and then click on Options.
In the Options panel, click on the Reminders section and check the “Periodically Remind me When I’m Not Timing” option. Also, enter an interval of time in hours, minutes, and seconds for your desired not-timing reminder.
Depending on your work schedule you can even narrow down the days and time range in which you should be timing tasks on your computer.
Below you can view an example of a not-timing reminder which appears after a desired amount of not timing any tasks: