I just researched this and took care of everything. You can wash everything in warm soapy water then boil them for 10 minutes and reuse them. The lines and membranes you d in a micro steam bag. Then wala ready . Also if you feel the lines aren't to your standard they often give u some in the hospital b4 u leave bc hospital pumps are medelas. Hope this helped.
(Boil the shields, bottles, caps, connectors (from shield to bottle) with the yellow part out (rock then pull off))
(steam lines and membranes)
Wash all first
From what I've heard Kia is right. Those Medela ones don't really require new parts unless something is broken. Everything is serilizable. I love that because it saves money and keeps plastic out of landfill. Go Medela!!!