Like every rule in writing there are occasions when it can be broken, if you do it consciously to achieve a certain effect. I write in third person limited but sometimes in the beginning of a chapter/scene I can use an omniscient pov to describe the setting of that scene. Like seeing it from above, from a little distance and with a greater perspective, and not like the character would do. Often it is a short description of the surroundings, before I zoom in and see what the character is doing. Sometimes I can also let a omniscient POV comment on something the character does or a choice she makes, because that is something I like in novels I read. When do you break the POV rules? Or do you strictly follow the same POV through the entire story?