It's a common question of new breastfeeding mothers. Should you feed a baby from both breasts at a feeding, or just one? I had the same question. This is what worked for me with my first child:
In the beginning, I nursed from both breasts, something like 15-20 minutes on each side, depending on how hungry he seemed. (I burped between breasts.) I was so engorged, both of my breasts needed the relief. As my son got a week or two older, I noticed that he started to have some green poops. My research showed that it probably wasn't a concern, but could be a foremilk/hindmilk imbalance? Well what the heck is that? I learned that the milk at the beginning of a feed is more watery, allowing it to come out faster to satisfy the baby when (s)he is super hungry. Toward the end of the feeding, the milk gets fattier and richer. This is the milk that can really help the baby gain weight. If you feed from both breasts, the baby will mostly be getting foremilk, and never get to the rich hindmilk. So, I switched to feeding from only one breast. The green poops were gone immediately. Wow! Our bodies are amazing, aye? If you are pumping, you can see the difference between foremilk and hindmilk.
I personally like feeding from one breast better anyway, and it is what most professionals recommend now. Who wants to unlatch a hungry baby and make him cry, just to switch breasts? Just let the little one eat. That's my opinion.
One more thing: when feeding from one breast: If that breast gets completely "deflated," and after say 25/30 minutes your baby still seems hungry, go ahead and offer the other side. The next feeding you would then start on that breast (the second breast from the previous feeding.)