By default, ssh-agent stores identities forever. It has an option to
set a maximum lifetime for identites (useful to expire passphrase protected
keys). Allow this option to be set using:
zstyle :omz:plugins:ssh-agent lifetime <time>
Implement a simple module that automatically launches the ssh-agent when you login and
adds your default key.
Useful for anyone that does remote work and thus doesn't have access to a keychain tool.