Addresses do not expire. You can use the same address as many times as you like over as many years as you like. As long as you do not delete the wallet file, or always have a back up, then you will always have access to that address. If someone has sent you money and you cannot see it in your wallet, then either they have sent it to the wrong address or your wallet is not syncing properly.

Address do get expire. You can find this in many large wallet exchanges or something.
Here is one example which proves address gets expired
https://bitcoin.stackexchange.com/questions/12536/sent-bitcoins-to-an-expired-address-how-do-i-get-back