I have been expressing since my son was born, initially as we had difficulty with bf and once rexolved (at 8 weeks) so my husband can give the last feed of the day, and to get a supply for when I need to leave my baby (not often) I express 3 times a day and average 200ml. Sometimes my son will take this much is his night feed, sometimes much less. When I end up with an excess I freeze it.
My HV suggested he may be lactose intolerant as his poos are a little vinegary. I researched on the net and it loooks more likely to be oversupply so more foremilk and not enough hindmilk - he also gets fussy at the breast, is very gassy and feeds very frequently. Problem is, I want to carry on expressing so he can continue doing the last feed (after the initial problems I find bf stressfull and some relief that one feed is not my responsibilty, maybe sounds odd but it works for me) but I also want my baby to be happy and satisfied. Any suggestions? The amount that i express at each session really depends on time of day, hydration, tiredness etc.