I usually call to confirm, not because I'm much of a worrywart, but it always seemed natural to me to check on reservations I made months ago, especially if there is no written confirmation. If you have the number given at the time you book, you should not have much of a problem at the podium.
Before my trip in May, when the reservation computer system was acting funky, they lost two or three arrangements I had made. I would not have known if I hadn't called. That was likely a rogue circumstance because of the technical difficulties.