I thought I'd share some advice that I wish I had received before I started pumping.
The Medela pump (I have the freestyle) is great as it's enabled me to keep breastfeeding through 7 months even though I have been full time at work since 10 weeks. That being said I have have had a lot of issues with it and it can affect supply. My supply definitely went down after going back to work, which I'm sure is in part because of undiagnosed pump issues. (I supplement with formula now.) Sometimes I thought I had a supply issue - but it was really pump related, so that's why I thought I'd share.
The parts can warp so you shouldn't dishwash them. You also need to be very careful with using the Medela sterilizing package. After too many issues - I hand wash them most of the time. In a pinch - I use the Medela microwave sterilzing packages
All pump parts are very sensitive to water. You have to make sure every part is super dry. A little bit of water can lower the pump suction so it seems like it's working but it's not working at full power. And you might not realize it.
I've learned that most working moms who attempt to keep breastfeeding for a year end up having problems (actually ALL the ones I have spoken with). The MEDELA CUSTOMER SERVICE IS VERY HELPFUL. Admittedly - they do not seem as helpful as they used to be (many people told me they were overnighted brand new pumps when they had problems. I have not had that kind of receptiveness, but I have had successful trouble shooting help and a new wire sent in 2 days). Save the cust service number and save the instructions manual!
These pumps is very sensitive and unfortunately - that means less milk pumped which could lower your supply
I actually had to use a hand pump for 2 days after my latest pump problem and found I am getting MORE milk with the hand pump than I have been getting for a while using the freestyle. I wonder if I have been having trouble with the wires for a long time but didn't know it completely went caput.
These are just a few things to beware of...