@marenas - Unless you are running the File Poller snap in an Ultra Task which will automatically restart the task as soon as it closes, I would recommend that you schedule the task for the minimum acceptable “downtime” in the event the File Poller terminates abnormally. As of the 4.26 release (Sep '21), SnapLogic enabled the Snaplex-based Scheduler, which means that scheduled task timing and reliability is dependent on your local snaplex and should be very close to the selected timing.
With that stated, you could set your File Poller to check for file existence as often as you wish, with the timeout set for 59 minutes (for example), then create the Scheduled Task to execute every 5 minutes with the “Do not start a new execution if one is already active” option enabled. This means that the polling would only be “down” at most 5 minutes every hour. Since the scheduler is using local snaplex resources, you could even have the task scheduled every minute if you desire.