Add limits for subscription interval

It would be helpful if we could be prompted for a date/time range in which to run a subscription. This way we can expire subscriptions, or only run them between certain times (working hours, let's say.) For example, in English:

Run this subscription every hour from 9am until 6pm.
Run this subscription every day at 9am until [such-and-such-date.]

Thanks!

-Mattyj