Eating at a certain time is a old fashion myth. However, eating late at night has proven to produce discomfort, at least for me. Also, it's a good thing to stop eating at a certain point as it can cause quite a lot of trouble (i.e. cravings for food or impulse eating).
As for rules, I must agree with Nae in that you shouldn't have rules. The reason being is that we're creatures of habit. Let's give an example, let's say every Saturday, you eat yourself a slice of pizza. Now, let's say this Saturday you ate something with a group of friends, but you didn't have your pizza yet. This could trigger your brain into saying, "Hey, I need pizza." Therefore, you are forced to fight a craving that could have easily been prevented if you didn't have rules on how, when, and what you ate.