Chuck and johnrover are absolutely right about the importance of accommodating these different types of repeating tasks. Once app I've seen for them is
Sciral Consistency (mentioned by mprewitt above). I doesn't seem have been updated recently, but it is definitely worth playing with the demo.
The visual representation of such tasks it offers is particularly nice (see the page linked above for a description)
I would love to see this sort of functionality, and a nice visual representation of it, in OF!