Every two weeks for the black bin where I am. But of course smug 4th estater's household only has to put the black one out every SIX weeks. Fixed charge too, none of that pay by weight faff either. The amount of packaging on stuff nowadays, and the newspapers, and the plastic bottles, and the tins means the Green one is out religiously every two weeks though, but that's free.
I can't remember when the brown bin is collected, I am cooking a heap of compost minus the food waste in it at the mo, mostly grass, cliippings, and deadheaded flowers etc. Couldn't stand the smell of the food, but it's going to be great in a few weeks, for the winter mulching etc.