I never used them when I use to pump my breasts. I use to insert nursing breast pads inside my bra to stop to catch any leaking. My breasts did leak a few times, which could have been embarrassing at work.
I expressed for about 6 months daily.. I used to express twice a day. I had access to a double electric breast pump, so I could express from both breasts at the same time. I used to feel like a cow. I never got too much milk, not enough to feed a baby fully. Toward the end, I got a nice flow going.
I really enjoyed the experience and would love to breastfeed a baby. I got fuller and more mature looking breasts, not bigger(tanner 5 breasts) from the experience and for me that was a permanent look. I know some woman's breasts revert back.
The only negative, when your breasts got full of milk, it would get a little uncomfortable. I remember toward the end of my work day, my boobs would get sore and I could not wait to get home to express.