Extend Key or Subkey
Keys created in GPG Keychain by default expire 4 years after creation. Should you ever loose your key or password, this ensures keys will not remain valid indefinitely.
Since GPG Suite 2018.4 users are warned before a key expires along with an option to extend the key for two years with a single click. You can also manually extend your key at any point in time.
To extend your key double click the entry in GPG Keychain to open key details. Click
Change… to update the expiration date.
Make sure to also extend the subkey by going to the subkey tab in key details. Right-click the subkey and select
Change Expiry Date to update the expiration date.
After updating your key GPG Keychain will ask about uploading your updated public key. We recommend to upload your public key as otherwise your friends won't be able to learn, that your key has been extended.