If you don't want to harvest worms from partially decomposed garbage and bedding, but do want high-quality vermicompost almost fully converted to worm castings, the trade-off is losing your worm population. Accepting this trade-off means adapting your own behaviors to complement this loss.
In a low-maintenance system, you might bury garbage in your bin for four months and then let it sit unattended for another three or four months. At the end of the seven to eight months, you will find a bin full of fine, black worm castings, but there will be very few worms remaining - perhaps not more than a dozen. These fine castings can be used as top dressing on your house plants and in your garden for a shot of nutrients. When you're using this system, you can compost your remaining food waste in your outdoor food digester or start a new worm bin.
High- and medium-maintenance systems require that you harvest the worms, or at least give them the opportunity to move into fresh bedding. For a high-maintenance system, plan to do this every two to three months. Medium-maintenance means going about four months before harvesting.
Harvesting methods include: