DD usually only ate from one side, but I always pumped both sides, since often I needed both sides to get a full bottle and also to save some if needed. Not sure how old you LO is, but when DD was very young and still eating 3x while I was gone, I was able to pump just 2x and have enough for all 3 bottles, and no issues on weekends (at 4 months we switched to only 2 feedings when I was gone so I was on her schedule again). I was pumping 5 days a week but never felt I had any issues when I was home with her on weekends.