For all my "adult" years, I had overly large breasts for my height/weight. My mom actually took me to a plastic surgeon for a consultation when I was 18 years old. This was back in 1982. The surgeon I saw then (who ended up doing my reduction when I was 27 years old, almost a decade later) told me at age 18 that I may want to wait until having kids-- especially if I planned to nurse. Back in 1982, the procedure didn't allow for post-reduction breastfeeding, I guess. Flash forward to after the birth of my first daughter, in 1990. When she was a year old, I returned to the same plastic surgeon in my hometown (he has since retired) and said, "remember me? I've had a baby, I've nursed her, and I still hate them. Cut them off". I had marked asymmetry which was facilitating the onset of Scoliosis. The aureole/nipples were displaced, at the bottom of my breasts, pointing downward. Years of huge breasts created those bra-strap dents in my shoulders.
My Dr. took measurements and photos, sent them to the insurance company, and I was approved for an insurance covered reduction with a lift. It was absolutely the greatest thing I'd ever pursued, (other than the tummy tuck I would have 5 years later post-twins). Here I am almost 20 years later, and my breasts are still lifted, symetrical, and much more in proportion to my body size. At the time of my reduction, I was, at 5'3", 105 lbs, and a E cup-- F while nursing. You could make beenie caps from the cups of my nursing bras. Dr. S took me down to a large B cup (though i begged for smaller, he said it would be disproportionate to go A cup).
I will say: if you are prone to gaining weight in your breasts, and if your breasts are the LAST parts of you to get smaller, when you DO lose weight, then you will be susceptible to having your breast "grow back", if/when you gain weight. Since 1991, I've weighed as low as 109, and as high as 169, non pregnant. But even at my all-time highest non-pregnant weight of 169, my breasts never got larger than a D. Currently, they are a large C cup, at 141 lbs. I didn't intend to have another baby after my first child and subsequent breast reduction in 1991, but I did end up getting pregnant with twins, which I had in 1993. I was able to successfully nurse the twins, no problem, post breast reduction.