I worked for a full day when my LO was about 7 months old and still feeding every couple of hours (when she was with me). If we were out she could go for longer. I had EBM stored but she wasn't interested and my DH ended up bringing her to me twice during the day. I was away for 12 hours and was able to manage just with the 2 feeds. My boosies were ready to burst when i got home though.