Yes, but which time limit? Even if it's every 24 hours, or 72 hours, rescraping a entire post can take a lot of space the way it works right now (where the entire post is saved, even if the difference between versions is a single character).
I understand. The concern is the space that the number of edited posts will take up.
Perhaps have a system, that after the second scrape that is already done, that does another scrape (without saving) and checks if there were significant changes (+x characters for example). If the number of changes is large, it saves this edit.