Camber as with toe can change for a number or reasons including kerbing your wheels.
Any work done on the front suspension such as top mounts, wishbone bushes etc should be followed by a full realignment, and this should include measurement of toe, camber and castor. Toe and camber can be adjusted on the front wheels but castor is not easily adjusted. As for the rears you can only adjust the total toe by adjusting the position of the rear beam mountings. Giving more negative toe to one side will give an equal amount of postitive toe on the other side, unlike the fronts which are independently adjustable.
A proper alignment will significantly change the way the car handles, turns in and reacts when you hit bumps/potholes.
I would agree however, that worn bushes will cause similar handling problems.