On a side note, it is better to use a password manager like [LastPass](https://www.lastpass.com/), then using the default browser solution (remember password) or not using anything at all.

There, you could set on which urls, which keys could be used.

Never enter your password/key manually, only through the manager.

If there comes a place, where that the password manager don't give you the option to input your keys, look carefully why. Is it phishing ? Be skeptical.

And don't forget to backup your password manager's data store (or as it is called for LastPass - Vault), preferably in an encrypted, password protected form, at multiple places, at least one of which is cold storage.