Well, I learned the hard way that on hive it is acceptable never. I reposted a handful of old posts that were originally posted more than 5 years ago on that other platform primarily because I wanted to correct some formatting issues (mostly broken image links) and was nailed by hivewatchers for my trouble.
I can definitely see how reposting your old content CAN be abusive but chances are, rewarded previously or not, there is a whole new audience 5 years later. Why should a new audience be prevented from rewarding your older stuff? People that have read and rewarded your content previously can make their own decisions.
Given the nature of hive and the fact that old posts typically aren't even seen, it seems like it should be reasonable to repost content after some reasonable time period. Of course "reasonable" can be highly subjective but surely in a supposedly decentralized system that can at least be handled by individual voters and not a self-appointed policing agency?
I get it, this is the real world and we have things like autovotes and other factors that skew things. Not that i have a specific solution but what we need is a smarter way to vote or a smarter hivewatchers instead of this one size fits all approach.