just a suggestion to auto close topics after a certain period of inactivity. There are almost no cases when a user responds to a month old thread and it adds anything new to the conversation, let alone some of the year old threads ive seen revived.
To me, four weeks of inactivity is more then generous before auto closing the topic.
Against
Necroposting is better than lots of duplicate threads with the same topic
Why are you assuming people would immediatly start a duplicate thread? Not sure there is any evidence to support this. Even if every user who would of necroposted started a new thread instead it would still be the vast minority of duplicate threads. Which are typically new users not using the search function.
Plus, atleast duplicate threads are moderated. Nothing is done about necroposting.
I think a year of inactivity on a thread is more than enough. Tech topics tends to move fast and update often until it stops for whatever reason.
After a year, significant amount of changes could have happened and the thread could be rendered obsolete with all said changes and at that point, it could be reasonably reposted and revisited, maybe?