Yes, this is very common. Indeed if used as a fileserver and by many users it is absolutely essential. SFTP uses SSH, and there is a lot of EDI activity that depends on it too.
From devices it is possible to trigger events with custom user logons (such as poweroff or reboot).
Consider also SCP (WinSCP is commonly used to access source code), and KDE users still able to use fish: in Konqueror.
Notable too is the use of additional ports in case of loss during maintenance (Ubuntu do-release-upgrade, say).
So yes, I gather you have never had multiple PuTTY terminals open ?
63Why didn't you just try before asking? – Dmitry Grigoryev – 2016-01-28T08:01:55.783
1Not only this, but you can have multiple links between the same pair of systems. You may also find
screen
ormosh
useful if you want the "Windows remote desktop" behaviour for the command line: a single interface which is passed around multiple links. – pjc50 – 2016-01-28T16:58:20.6477There are 2 reasons why I didn't simply try before asking; the first is the lack of faith I have in my own understanding of linux - if it had worked I would have still not trusted its reliability if I come to rely on it. The second is the the Superuser community is, generally speaking, awesome and quick to help those who ask - thanks community. – Sam3000 – 2016-01-28T17:40:15.307