We made a big church government switch six months ago, away from the traditional deacon-led system in Baptist churches and installed our first elders. With some other reorganization of committees and ministry structure, they've been quite busy.
As of now, they meet weekly, although once all the change settles in, they say every 2 weeks is more likely. I doubt it will ever become less often than that. We only have 5 lay elders (and 4 paid - the pastors), for a church with weekly attendance around 400. They have quite a lot to do.