Some Gardeners turn compost regularly to ensure that all materials are heat processed. Frequent turning speeds decomposition, but isn't required to make compost. In Colorado, it's best not to turn compost after December. Turning allows valuable heat to escape, and may stop processing in cold weather. To restart active processing, turn and mix in fresh materials with the winter compost.
Processing occurs faster when materials are mixed together, rather than layered in the bin.
Compost is ready to use when it has shrunk to one-half its original volume, has lost the identity of the original material, and has a pleasant earthy smell. Permission is hereby given to duplicate this Plant talk Colorado TM script as is if credit is given to the sources.