For you ladies who have already had twins, do you breastfeed or exclusively pump?  Just wondering how challenging each if these options are? I am hoping to do a bit of both in a perfect world but would love to hear the good and the bad of either.   I will obviously use formula if needed but would love to avoid the cost of that if possible.  For those that breastfeed, do you tandem feed them or one at a time? At what age were you able to do this successfully on your own?