Question: I was wondering if the "Polling Interval" could have a few more options to it?
Potential Solution: Adding more options to the drop down box. EG. 1 per month, 1 per week, 1 per day, ect. Maybe adding the option to select a specific day for the appropriate options. Otherwise you could change the drop down list to a text entry box. This could be filled with some notation denoting a wait period. EG. minutes, hours, days, weeks, ect. Or you could combine these. The number field would be variable and the measurement could be a drop down box. EG. 720 | Minutes, 36 | Hours, 7 | Days, etc.
Rationale: I have some feeds that are updated rarely and don't see the need to poll them every 2 hours to find that nothing has changed. I also have other feeds that are only updated on specific days of the week.