[Leon]

This is going to be very personal in valuations as each person will have their ideas, relative to aesthetics and their own tendencies. For me once a card is trimmed or altered it certainly loses some of its value. It's all about aesthetics and the rarity of the card after that. If it is super rare I might not diminish the value as much, especially if it is a barely noticeable trim. If it is a whole border or more, then the percentage of value loss is greater. If the card is a more common card then any trim is going to affect it more drastically than a more rare one. With the advent and acceptance of AUT grades the prices have certainly risen on altered cards, imo.