I've known a few girls who broke the D cup barrier, and back pain tolerance is apparently relative but there is a certain weight they have to be compared to the body in some cases before the reduction is covered. A friend of mine, 5' even, 34DD, maybe 130ish, has never complained of backpain but has contemplated a reduction. She specifically pointed out at some point how much they weighed and what they would have to weigh in order to get a non cosmetic reduction. Another friend of mine, around 5'2", 32C-34D depending on her weight because she fluctuates dramatically, has always complained about them and constantly talks about wanting a reduction, using phrases like "I wish I could just hack them off." One other example, an extemely thin girl I know who is a D, less than 100 lbs, 5'3", loves her breasts and would never get them reduced. Hers sag the most though of the 3 however. So that's 3 girls all around the same size, 3 different perceptions of their big boobies, and pound for pound the smallest was the one who wanted them gone. So where is the line drawn with actual debilitation and clinical weight measurement, and straight up big breast shame?