Light effects during drying

I am curious... How important is drying buds in the dark? I ask this because i have seen and heard about its importance many times. However, recently i was at a buddys who has been growing for years, and always producing great weed. I walked into his house to find 5 or 6 plants hanging from random hooks in the ceiling... in the middle of the house.... like it was nothing. surrounded by light most hours of the day....(even night time because they are in the family room) Mind you he is one of those growers that just happens to be really good at it, while not really understanding what he is doing... My drying closet is small (4x4x6) and the humidity quickly rises to 50percent or so... I am just curious as to how much damage light exposure can really cause... if any? I feel like a little light cant be that bad and drying in high humidity seems to be worse... All opinions welcome! thanks!

The highest contributor to THC degradation is light, followed by heat and oxygen. The amount and time of exposure is going to determine how quickly it degrades. The studies I have seen have indicated losses up to 10% in 4 months or so.