I don't know that people that calve later do it out of laziness :? We always calved Jan-Feb.We don't have alot of building to put cow-calf in,were freezing calves ears,scours were rampant,calving in -40 is NOT fun! We now calve March-April,last three years we've been at 100%.No frozen ears ,no scours.Ma mas and babies do way better.Don't do night checks anymore,don't need too.Like was said before whatever works best for your outfit....like Greg said he was a Kit follower and didn't know it..lol