Can the bitcoin deposit address associated with my account expire?

Yes, so you should always check before sending a deposit to make sure you're sending funds to a good address. We're not responsible for funds sent to an expired address. You are allowed 5 bitcoin addresses before any start to expire. So if you don't create more than 5 addresses, none will expire. But once you create 6 or more addresses, one or more addresses will be automatically set to expire. If an address is set to expire, it will be clearly marked - the address will have the status "expiring #" where # = number of days remaining (starting from 7) before it expires. We recommend that you stop using an address that is set to expire as soon as possible. You can't choose which of the addresses is set to expire but we plan to offer this option later. An address just marked as "Used" is OK to deposit to so long as there's no indication it's set to expire.