I don’t want to stifle discussion, but we also have had a problem with folks reviving ancient topics (despite the warning on topics older than 90 days) so we’re just rolling out auto-close now.
You can just hide it with CSS. There are a bunch of topics about hiding other stuff (search “hide css” if you want to figure it out, but hopefully someone else will give you an actual answer.
With the ‘after last reply’ ones, the timer gets reset when someone replies So if you had ‘1 year after the last reply’ it will stay open for at least a year, but would also continue for another year if someone posted again (eg. a post out of the blue on day 364 would reset the count to the full year again). There is the option to just have a straight ‘this topic will close in 1 year’, which won’t reset when people post more replies.
I thought perhaps having a shorter ‘after the last reply’ timer may solve your issue with not wanting a huge time duration displayed at the bottom. The topic would still stay open for as long as people were replying + the timer duration.
As @pfaffman says, you can hide the topic-timer-info with a little CSS, but I don’t think you can easily make it reveal itself when it gets closer to the due date.
.topic-timer-info {
display:none;
}
Extra details on how to add it to your site
Go to /admin/customize/themes
Click on install and then create new
Give it a name, and select ‘component’.
Create
Add it to your theme
Click on the Edit CSS/HTML button and paste the code into the Common tab