Question for moms who pump at work

So I went back to work last week. I usually feed my 8 week old before leaving (around 5:30 am) and then pump at 9, pump at 1, and breastfeed when I get home around 3:30. I pump around 12 ounces at 9 and around 8 ounces at 1. This weekend I pumped once each day while feeding on demand whenever my son wanted (atleast once every two hours but usually once an hour, he's a hungry little guy!)

My question is: do you pump when you're not at work or just feed on demand? My breasts are slightly painful and I feel full no matter if I pump or he eats. FTM and just curious about keeping my supply up and making sure I avoid mastitis or anything!

Thanks!