Breasts are always changing. While I don't think you'll see growth such as the difference between early puberty and early adulthood, you can expect some changes to take place. Little changes such as lumps from cysts (fluid filled sacs) become more and more common the older you get (especially after 30). (Although these could be more than cysts so if you have a lump or change definitely talk to your dr, just in case.) Your breast tissues also become less dense with age. So at 50 you will have a higher fat to breast tissue ratio than you would at 20. Big changes though would more likely come from weight gain or pregnancy. In my own opinion, unless you started puberty very late (15-17), your breasts are likely done "growing". They will swell and may gain a size or three (depending on how much weight you gain) if you get pregnant and they can easily add a cup size with smaller weight gain too (10 lbs).