best practice is not to re use addresses. You get one transaction per address, and then you can sweep it.
Thanks but that's what I will be doing anyway. After sweeping, the address will be taken out of the "active_addresses" list and won't be checked ever again. This detail however doesn't make downtime any better. When the Bitcoin payment processing daemon is down, I won't be notified of the new transactions. BitcoinJ, when catching up with the blockchain, refuses to notify me of my transactions.