If you pump with a Medela PIS, how often do you replace the membranes? Yesterday I thought maybe I needed to replace because my output was TERRIBLE, but then as it turned out my LO didn't finish all of the bottles I left her that day so I was able to get away with not having to go into my frozen stash for today (yay!)! Today my supply was back up to normal...weird. Anyway, yesterday I thought maybe I needed new membranes so I ordered a bunch on line, but then after today...I don't know?
Just curious now how often those membranes need to be replaced.