Would be helpful if GpgOL would show a hint when the own key or that of the recipient will expire soon (in less than 7 days or something similar). Then you have more time to renew the key are create a new one and don't get into a situation where you have to write an email urgently but first have to manage you key. You are also able to remind others of the expiration of their keys.
On the screenshot you can see how it looks like in Kontact e35:
Good timing. We have just added the necessary bits to the shared libkleopatra. They just need to be used in GpgOL. See T6330: Kleopatra: Additional Expiry handling.
The default time period for warning about pubkey expiration is 14 days in the old Kontact (IIRC).
The wish came from an organisational GPGOl user (who had said thank you after I've gave the hint from my old Kontact/Kmail. He/she would not have noticed the situation until the next attempt to use the key.)
In current Kontact and now also in Kleopatra, by default, it's 30 days for own certificates and 14 days for all other certificates (including certificates in issuer chains), but Kleopatra currently doesn't notify the user about expiring issuer certificates.