Re: should a 4 month old be on a routine by now?
At 4 mos my DS was still eating 12+ times a day. If I was working dayshift I would wake him to eat around 6 and he would eat every 1.5-2.5 hours all day, sleeping maybe 45 min at a time and usually eating to sleep and upon awakening or shortly after. He was however a great sleeper and would sleep from 10-4 at 6 wks and at 4 mos was sleeping from 9-5:30 or 6 (which is what he does now at almost 6 mos, unless he rolls onto his stomach, but I digress)! I think it is more than fine to follow his cues. I made sure I went over them with my DCP and sent milk in small amts and made sure she knew that milk could be reused etc so she wouldn't waste it. It does get better, he will space out his feeds better and may do so more for the DCP as she might feed him larger amts at a time. You will find that if he eats frequently during the day you will need to pump pretty frequently at the begining. I pumped every 2-3 hours when I first went back (12 wks) and now it's more like 4-5 hours.
DS 2/06 nursed x1yr
and DD 3/08, so far so good!