Ya, we hate having to do this, but we've had cases where there have been big problems. For example someone forgot to logoff and then an upset sibling went onto their computer and deleted / edited a bunch of their posts and replaced the text with really bad stuff. It was a nightmare for the member and those reading the very popular thread.
We know there are cases where really old threads are updated over time, especially the first posts. We do like these situations and have a workaround:
Old case: You start a thread like "People who love Buff Orps" and in the first post you update / edit it with members who join, events, etc.
New case: You start a thread like "People who love Buff Orps" and in the first post you LINK TO a BYC PAGE and update / edit it with members who join, events, etc.
One of the HUGE pro's of the new use case vs. the old one: You can grant 1 or more people access to also edit a page and help you keep it updated instead of you having to do all the work! There is also a history of edits on pages / articles so you can see what was changed, when, and by whom.