Where to Guard when Punching

Karate, Kung fu, Boxing, whatever you fighting style, as long as you punch, there will always be the need for a guard. Unlike kicks, when you punch, unless you are extremely tall with long arms, you shall also be in reach for your opponent to punch you back. This is where your guarding hand comes into play. Boxers and most martial artists nowadays tend to have there guarding hand clenched as a fist, and held near the cheek area protecting the delicate chin. An argument to this is that if you are wearing big boxing gloves which increase the size of the guarding area and provide a cushion if hit, that is fine, but what if you are not. The fist without gloves is small which may not guard enough and there is no protection to the front face area. Some people believe that the more effective guard would be an openhanded one held in front of the face which protects the facial features, but then again it doesn't protect the chin which if struck hard, is the best way to score a knockout. It could be said that it depends on the situation. In a boxing match a guard on the side of the face could be appropriate, where an MMA fighter might prefer the in front of face guard. Also, in the street your guarding hand could be used to grab the opponent or to control his arms which could allow for a more accurate strike. In my opinion, the situation decides the position of the very important guard, but it must always be in the back of your mind when punching.