Best Practices for Tickets with no Customer Response

How should a support agent deal with unresponsive users - who create tickets and then don't respond? ITIL tells us an incident should only be closed by the user who created it. Otherwise the ticket should be put "on hold". But in reality... There's only so much you can do:

1: Give it another try then close

Send another message asking if they need any further help and then close the ticket if there's been no response after a couple of days.

2: (Semi) Automated followups

You can copy-and-paste your last reply a few times, either manually or automatically, if your help desk software support some sort of scripting or scheduled automation. Then close the ticket.

3: Auto-close

We have a handy feature in Jitbit Helpdesk: if the latest reply was from techsupport and the user hasn't responded within X days - close the ticket.

I did a quick search through some techsupport forums and subreddits, and it seems everyone agrees on closing the ticket after a few attempts and/or days. Either way, this needs to be clearly stated in your SLA: how many attempts are made, over how many days, should there be a mandatory voice call attempt or not - have it in writing. Then implement it - if possible - using some sort of scripting automation.

P.S. As always, the best rule is - be a human, not a robot. If a user says "my Internet is down and my email is not working" - sending more copy-pasted emails and then closing the ticket as a "non-response" isn't the best idea.