We use a secondary for our wit because we don't filter the hops or orange peel out before putting it in the primary. This results in the primary being pretty gross by the time the ferment is done, and will clog spigots and siphons. We usually give it a week in primary, rack to secondary off the gook and give it another week. At that point we either bottle or keg, bottling obviously lets it age further, but if we keg we usually give it another week under pressure. So all in all, three weeks start to finish, primary, secondary, keg. We also try to brew every weekend, so we need to free up our primaries, and secondarying (word?) allows us to do that.
mike