It is a matter of whether anything useful is being said in the new post. Even a very old topic can be reopened if there is some new information on the topic that would be of real interest to others.
On the other hand, a “me too†tacked onto a topic that has been resolved a couple of weeks ago shows poor judgment.
There are many instances where it appears that the late-poster has read only the last post and did not read the topic from the beginning to understand the context.
