I've ssh'd into colleagues' machines to help them with system problems, and they've ssh'd into mine to retrieve their VPN keys. Not all of my colleagues have ssh access to a common server somewhere.
I've also remoted into my workstation from home to do emergency work.
Ideally, those colleagues would keep sshd disabled unless they actually do need your remote assistance, at which point they'd "service sshd start" or "systemctl sshd.service start" (or however it's normally done with systemd) or "/etc/init.d/ssh start" or "/etc/rc.d/rc.ssh start" or what have you. Minimization of attack surface is an important part of a comprehensive security strategy, and a remote login system - even one with a phenomenal track record like OpenSSH - contributes pretty heavily to that attack surface.
I've also remoted into my workstation from home to do emergency work.