Hi Kristen! My four were EBF also before I went back to work each time, so I totally know the feeling of guessing how much baby will eat. You're right that it's trial and error. For me, it works to pump 2x/ day (once in the morning, once in the afternoon). I get about 8-12 ounces each time (depending on if/when my daughter nursed in the morning before I left for work). For the first couple months after I returned to work I also ended up pumping right before bedtime if my daughter didn't completely empty both breasts before she fell asleep. That helped augment my stash for those days when my supply was a little lower and I didn't get as much during my pumping sessions. I'll occasionally also get in a pumping session over the weekend if I'm starting to feel "full" even after she eats. I feel like my stash has been pretty stable over the past 3 months - I can roughly replace what she drinks at daycare (20-ish oz). Now that we're creeping up on 6 months and I'm starting to think about solids, I'll continue to pump 2x/day anyway. That way I keep "wiggle room" in my stash (again for those times I only pump closer to 16oz total on a given day). Hope that helps at least a little! That's my two cents, anyway... 🙂