To clear or not to clear that is the question

Hello everyone,

 I am building the far west trucking truck and trailer and this kit has a giant decal for the trailer, I have successfully applied the decals to the trailer but now i have a question, to clear it or not to clear it? I have never applied a decal this large and my thought is that over time it may tend to dry out and come off, has any other builder applied clear coats on top of the decal or does it look more natural to leave it alone?