You can withdraw as much as you like but usually people don't use paper wallets for more than one transaction because the whole point behind having a paper wallet/cold storage is that it's keys have never seen the lights of internet, once you import it to your wallet it is no longer a cold storage, unless you're importing it to a cold storage machine to just sign the transaction. Say you have 1 BTC in your Paper wallet and you want to send 0.5 BTC to 'A', so what you do is send 0.5 BTC to 'A' and the rest of it, 0.5 BTC to another paper/cold storage wallet and you never use the same address again and it's considered the best way of keeping your bitcoins safe.


It's kind of cold storage, that's the basic purpose behind it and if you print it on a good paper and have it laminated you can keep it for a long period of time without having to worry about your USB or Hard drive failure.