I sometimes find it hard to distinguish between "patina" and "damage". I get that tritium lume sponges or shrivels up a little bit naturally due to age, but sometimes it darkens? I get that some dials change color over time due to UV light, but sometimes random "spots" appear on it? I have no base knowledge on chemistry to understand why these happen. This is why I find it hard to get into vintage watches. The chemistry behind "patina" is too hard to fully understand.