I've been bfeeding my DS for 21 months and my left boob, very early on, became the preferred one - much faster flow and seemed to always been in plentiful supply. However, I made a conscious effort to keep the feeding even on both sides. But after about a year I was probably doing one feed on the right to every two on the left. Now, after nearly two years obviously they don't really fill up and I'm only feeding DS once in the day (but still A LOT at night, frankly, terrible sleeper blah blah blah) but the size difference is ridiculous. I'd say left is a D cup and right is barely a B cup (pre-pregnancy and BF I was a B cup). Will they eventually even out after I've stopped breastfeeding?! I know most women have slightly different sizes, but this is soooo noticeable. I feel ok about hiding it for the time being as I'm still feeding but I don't want it to be a permanent thing!