This may already exist, but wouldn't it be useful to automatically lock threads after a certain length of time? (One long enough so that it is definitely dead when it happens)
The idea you suggested is not as good as it sounds because some old threads can be revived with the right post, and necros aren't so common that mods get swarmed with reports of them.
A necro isn't always a bad thing. If there is value to be given to an old conversation, we look at it on a case-by-case basis. Mostly though, the value is not there.
i would only have it auto locked on ones that havent been used in months, other wise it wouldnt be no point because some posts are easy to revive even after a week or two of not being used
