Guys you're talking about two different things. Rich is talking about micro cracks or alligatoring and you guys seem to be talking about crazing.

What Rich is talking about can not generally be seen by the naked eye and usually requires at last a Loupe, like a photographer uses, or a magnifying glass.

Once alligatoring begins it creates a large amount of surface area for the UV to attack and only serves to accelerate the degradation process. A smooth polished surface to the gelcoat leaves less surface area for the sun to attack. I see lots of people stop buffing at a compound and never move to a true polish or glaze. Doing this will leave micro swirls, we've all seen swirl marks on a black car, which can also shorten the life of gelcoat. The peaks and valleys of the swirl marks or alligatoring both create lots of sun loving surface area to get devoured by UV..