I've heard from some people that these need frequent replacement but I haven't had to replace mine yet and they are used several times a day for the past 6 months. If I have an issue with suction, I check and make sure all the little flaps are in their notches (usually just pop open and then reclose the cover without having to move anything, it just pops where it should). If all those are in right and I'm still having a little bit of suction issue, I just crack the seal on them WHILE pumping to get more air into the system and it works like a charm. Only have to do that occasionally and only at the start of pumping, from there on out its great.

I have this system and feel it works fairly well. My only frustration is that after a few weeks the parts start to loose suction and need to be squeezed together to maintain good suction leaving you less than hands free. However, when it works it works really well. I have to pump 3 times a day at work and mainly pump at home too.