Organic matter > compost > soil
The longer it has been, the more will be converted to actual soil by the worms/bugs/micro-organisms. It doesn't "go bad" per say. As it turns to soil scoup it out and put it in another container. Sift out the worms ect an put them back in the compost bucket. Just keep giving more organic material so you don't get this nice and healthy pile....and then kill all your helpers.