According to How to set up a secure offline savings wallet,
Every time you retrieve bitcoins from your savings wallet, create a fresh savings wallet by repeating the above procedure, and send all your remaining savings balance there.
Why do you need to create a fresh wallet after retrieving a few bitcoins?
Is the receiving address no longer valid?
How can you create a secure offline wallet, send bitcoins to it, and then test it to make sure that it works by sending a small amount out?