Thankyou Kathy for taking the time to answer my letter
As I said in my 2nd post on this to Lactnet, perhaps there is a vast range of what is OK.
In my experience (homebirth and hospital birth) I see some mother-baby pairs who by the end of the first week are so efficient at transferring the milk from breast to babe that the time spent at the breast is quite short.  I don't watch the clock, but say 10 minutes or less on each breast.  The mother's let down is effective, the baby's attachment is good, and the baby 's sucking patterns are well co-ordinated.  The baby then has the look of ''I don't care what you do to me, I'm satisfied"   On the other hand I see babies who have to work much longer and harder - sometimes they slip off, and have to start again, sometimes it seems that they are only getting a slow flow of milk.  I think that within this enormous variability almost every mother-baby pair can function well enough to meet their own needs.  
I describe this to my clients like this: '' you can drink a can of coke slowly through a fine straw, taking small amounts over a long period, or you can drink it quickly through a big straw in a short time''.  I feel this is a simple practical example which anyone can understand, and the mother whose baby takes small feeds frequently accepts that that's the way her baby is, as does the woman whose baby takes it all at once.  I don't see one as better than the other.  I think it also gives a logical explanation to why good research has shown that the imposition of timed feeds has a negative impact on breastfeeding.
New mothers are vulnerable to suggestion that they are doing something wrong.  I try to encourage each mother to feel she has authority for her own breastfeeding, not worrying about how she compares with her sister and her friend.

An interesting aside to this discussion is the way other mammals nurse their young.  Pigs, for example, when in the farrowing crates that don't allow the sow to move out of reach of the piglets, have a brief letdown about once an hour, and there is a "feeding frenzy" that lasts a couple of minutes; the letdown lasts only 30 seconds.  The smaller piglets may miss out on the letdown if they are not quick enough.  However in the wild the sow has a nest, which she leaves when she goes out each day for lengthy periods to forrage for food.  She could be gone all day.  Many other wild animals (non-primate) have similar behaviours.
A number of herd mammals (such as horses, cattle, sheep, goats) have a ''nursery'' system, to allow the mothers freedom to feed themselves while the young are safe.  Primate babies hang on to their mothers while the mother is forraging.  
It has been stimulating to think through some of these issues.  Midwives in Australia have been told by mothers that one of the most distressing aspects of postnatal care is ''conflicting advice''.  With a system as diverse and interesting as human breastfeeding I wonder if agreed standard advice on something as basic as how often to feed the baby (other than the ''whenever your baby is hungry'') will ever be achieved?

Joy Johnston, Midwife FACM IBCLC
Melbourne Australia