The Periodic trigger lets you execute a macro at specified intervals while you are logged in.
The Period of the trigger can be set as follows:
Caution: Generally it is recommended to not use very frequent intervals (like seconds), except as a last resort. For one thing, a macro triggering will cancel any “once” or conflict palette choices or the like, and so frequent timed trigger macros will likely cause problems with that.
Note that periods that cross midnight will stop at midnight. Use two triggers if you want to trigger continuously before and after midnight.
You could use a trigger like this to run periodic maintenance or track changes.