I give them 5 to 7 days to make payment but normally send a message if payment isn't made after 3 days. No payment just lodge a non paying bidder dispute (people have a limited amount of non paying 'strikes') and then relist - the non paying bidder dispute takes a while and basically ensures you get any ebay fees refunded to your account.
If you have a look at ebay policy though http://pages.ebay.com/help/policies/unpaid-item.html
If a buyer doesn't pay within 4 days, sellers can open an unpaid item case in the Resolution Center. If the buyer still doesn't pay or reach some other agreement with the seller, eBay may record the unpaid item on the buyer's account.