That should be the absolute minimum. I don't understand why so many people go through the effort of cold storage if they don't use a passphrase, which would increase their security considerably with little additional effort.
How secure to have pass phrases ? If anyone know the private key how long it takes them to guess whether additional pass phrases exist or not ? What about giving to someone your private key and having funds in pass phrase wallet ?
I don't have cold storage yet Because I don't see the point of buying for the amount of btc I have now (but in the future when i will stack more sats maybe)