I feel like closing off a post after 2 weeks is too short. Sometimes issues or ideas stay relevant for weeks or even months, but if there's a lapse in posting on it then it winds up with no one able to post on it. So my idea is to increase it to a month. It won't solve the problem entirely (the only way to do that is to remove it entirely, and that would mean it wouldn't serve it's original purpose), but it would certainly help. And you should really create a system that automatically locks threads after that time passes, it's too much of a hassle to check the date on the last post every time I want to. Auto locking would also completely eliminate necroposting, because 99.999999999999999999% of necroposts are accidental.