Once baby is born and you have decided to breast feed the midwifes at the hospital will talk about the "fore milk and hind milk." This is the way the milk is produced in the ducts of your breast. The fore milk comes first and the hind milk afterwards. What they don't tell you is how long this process takes when feeding baby. Having worked with so many breast feeding mums over the years my judgement is it takes 15 seconds for baby to stimulate and suck before the milk starts letting down, sometimes less if mums has a lot of milk. It takes about another 30 seconds for the fore milk to come and then about another 30 seconds for the hind milk to come. The whole process is very fast and under two minutes. Once your milk has 'come in' at week two or three baby does not need much more than 10 to 15 minutes on each breast which includes burping time before baby has had a full feed.
If baby was given a bottle with a much more controlled flow with a teat size baby would take no more than 20/25 minutes with burping to finish a feed. So it makes sense for breast fed babies to be the most efficient. By 6 weeks babies have become even more efficient and despite drinking more milk at each feed this time is now down to 15 minutes per feed for both breasts with winding. By 4 months of age and baby is taking even bigger feeds, feeding time will be 10/15 minutes for both breasts and includes time to wind. Any longer and baby is dozing or falling asleep or using the mother as a human dummy!