If you did weekly rentals, you'd only get 1 credit for each of the rentals (and that's assuming you could work around the "consecutive" rentals part where you can't earn credits for consecutive rentals. On a month-long rental you'll earn something like 7 credits for the month, and if you did the rental as two months, it shouldn't hit the consecutive rental part (I know we've done several rentals that were just over 30 days, and they'd end up showing as a 30 day rental, with the 7 credits, then the rest of the time period, and would still earn credits for that period).