How to avoid user from running the same task too may times in the same period of time?

Hi all,

Good Day. :grin:
My task agent often stop working recently. Upon checking the system monitor, a lot task is stuck at Schedule and none in Active. And I notice there are tasks which are similar and are running by the same user.
How do I control that? I am thinking to apply some countdown timer to the Print or PrintPreview button but I am not sure it is the proper way.

Please advise. Thanks in advance.

Sorry, I forgot to add in snapshot.