Me experience and observation is that it depends on the elders. There are elders who looooove elders meetings, and just as many who want to put those very same elders in a meat grinder and turn them into alpo.....
Typically, it is an update on a judicial committee meeting. If the PO gets some letter from the branch or the CO, they might call an elders meeting to read the letter. (The Secretary is suppose to pass it around, but a lot of PO's want to make sure all the elders read the letter.... weridness...)
In some congregations, there is the occasional, chiwawa like elder who will call meetings for whatever may pop into his head. He is typically hated... lol