As far as I knew, downloads didn't use stock. How do I set the downloadable product to use the stock? And to make the product "disappear" from the catalog once the quantity goes to 0?

Manually deleting items means I have to go through all the orders for the past however long since I last updated and make sure I am only deleting the sold items. If I only update every 6 months then that could get to be quite a chore. The auto deletion is looking like a pretty good idea because it will save not only time but a ton of headaches. I just need some help on implementing it.