What are "recurring events"?

Highwest

(I really do search for an answer before asking basic questions like this! ;-)

I'm experimenting with adding a new event that more closely approximates what happens in real life. I noticed for "Gate Lockout" -- which I assume is a standard event that Sitelink provides by default -- there's a note: "Repeating events are not available as prerequisites for Gate Lockout."
What are examples of "repeating" or "recurring" events?

BusyProperties

When you set up an event you can choose to repeat it or not by the check of a box. My past due notices are repeated but my overlock is not so on mine the only option it gives me under gate lockout is overlock. 

MamaDuke7

The only thing I have recurring is late fees.  That's because they get one each month even when there is the previous one pending.  

Anything else, you only want to happen as the past due event happens.  Like a Preliminary Lien Fee only happens once until it's paid.  Then if they go late again it can happen again.  But it won't add a second one if the first one is still not paid.