You don’t have to follow any of the “rules” of photography to end up with a good photograph. What’s probably the most important is that you make your choice for a reason. When you take a picture and choose where something goes in the frame, know why you’re doing it. An example of a rule-breaking image would be to have a person facing left and placing them in the left third of the photograph:
You might choose to do this because you want to draw the viewer’s eye away from the subject and make them look at the space behind the subject’s head. In the background, something’s happening that’s slightly out of focus. You could argue that this is a way of depicting a subject trying to remember a past event, or being lost in a half-memory. This may or may not be the most successful way of getting such a message across, but it’s a reason to try breaking one of the “rules” you’d generally adhere to when composing a photograph.
If you’re just trying to take a pleasing picture, the rules are your friend. On the other hand, if you’re trying to convey something with the photograph, figure out how you want to convey it and compose your image accordingly. This may or may not involve breaking the rules, but you increase your chances of ending up with a compelling image if you choose a specific composition for a specific reason.