If you're afraid you lose both your main key as well as your backup key at the same time before you were able to reinstall another backup key you can ensure you have more than 1 backup key, and/or (re)consider where you store your backup key(s).
Also, it depends on where you are using the YubiKey. If its an online service you may be able to identify yourself via alternative ways. If its your FDE, you're hosed. Or you have backups. Either way, the above still applies.
If you're afraid you lose both your main key as well as your backup key at the same time before you were able to reinstall another backup key you can ensure you have more than 1 backup key, and/or (re)consider where you store your backup key(s).
Also, it depends on where you are using the YubiKey. If its an online service you may be able to identify yourself via alternative ways. If its your FDE, you're hosed. Or you have backups. Either way, the above still applies.