it depends i am a server & i work banquets i can work anywhere from 5 to 10 hours a day. but in case your job is acting funny about letting you pump it's against the law for them to deny you that right. look it up if you have any questions. i try to pump every 4 hours at work & I'll pump whenever my son wakes up at night. i usually pump a 6 oz bag at night both sides & one at work depending how long I'm there.
I went back at 8 weeks. I ebf & just pump at night & at work so he has milk when I'm not home. My son is 3 months old now. if you try & believe you can do it it is completely possible. it'll be hard at first especially getting a supply of milk in the freezer started but once you got a good amount you'll feel it gets easier.