There are some people who need to eat every few hours for biological reasons, so let's not start talking hard and fast rules here
For instance people with sugar sensitivity (hypo or hyperglycemia, diabetics, etc) need to eat regularly to keep their blood sugar in a correct place.
I think the general best way of thinking about it is to trust your body. If you are meeting your caloric needs and aren't hungry at 8pm, don't eat! If you're ravenous, your body is asking you to feed it, so have a snack. Etc.
I'm 198 this morning, so still have most of the 'decade' to go... But last Wednesday I was 199.8 so I'm making progress!