Worm compost (vermicompost) is composting accomplished with earthworms. It will contain a mix of composted and partially composted materials with worm castings (worm poop) mixed in. The longer the worms remain in the composting material, the more castings will accumulate. When the castings become the dominate material, the worms will sicken and eventually die or crawl off.
The more castings contained in the compost, the richer the compost. If you are composting with worms, you will want to remove your worms from the compost before it becomes too concentrated with castings to insure their health. Simply move them into another bin of fresh bedding.