Q&A: Can I Pump Less Often At Work?
It is a good idea to plan on pumping roughly every two to three hours while you are at work, though this can vary a bit depending on your job and how often you're able to drain your breasts throughout the rest of your day.
The important thing in terms of maintaining your milk supply is for you to drain your breasts at least seven to eight times per 24 hours (more is great). So if you are feeding your baby frequently during the night, for instance, you might be able to go longer during the day without pumping.
Most moms who are working full-time find that pumping at least once mid-morning and once mid-afternoon seems to work well for them.