As a serious answer, the change in routine will depend upon the routine. One that is aimed at strength will not necessarily change the core exercises, but will rotate accessories as needed or for something new. One aimed at hypertrophy requires sticking at exercises until you have achieved a certain goal (lagging parts, strength peak, time period, etc) but rotating the order or the like. I think the most important thing we don't seem to see enough of is the dropping of favourite exercises. I've just started BB benching again after 6-8 months off, I used the floor press and incline DBs instead. I'm due to swap back to the back squat after using the front squat, but I still want to hit my goal front squat before I do.