“When selecting a breast pump it is important to keep in mind that there is no such thing as the perfect pump,” says Ward. That being said, she explains that the most important thing to focus on is how the flanges fit. “If the flanges are not properly fitting, this can cause pain and abrasion to the nipple as well as the potential for minimal output,” she adds. As for the pump itself, it’s often not clear whether or not a pump is a right fit for someone until they’ve been able to use it a few times, so there’s no way to know for sure if it will work before you actually try it out.