Dalia asked about storage capacity of breasts.

Breast storage capacity probably doesn't change between babies. Once the milk-producing cells are finished growing by around 6 weeks postpartum, no further cell growth takes place for that lactation cycle. This appears to be genetically driven. Research shows that once the cells are grown, they secrete milk at different RATES in response to the baby's needs - they respond to the baby's growth spurts by making milk faster for a while. This is what "supply and demand" is all about - not increased/decreased cell growth in the breast.

A more likely explanation for different babies feeding patterns is that "babies are different." A baby with an "iffy" suck will feed more often just because he's less effective in getting milk. A baby with different genetic material might need to grow taller and heavier than her siblings, or her growth spurts are at different times, etc. 

Linda Smith, BSE, FACCE, IBCLC
Dayton OH where it's cold and dreary today.