http://www.medelabreastfeedingus.com/forums/14.aspxGet answers to what will work for youenCommunityServer 2007.1 SP2 (Build: 31113.47)http://www.medelabreastfeedingus.com/forums/thread/1966.aspxThu, 11 Dec 2008 23:19:58 GMTa3cad0db-79cd-4fbb-918f-5e54bdbae2d2:1966mrspib0http://www.medelabreastfeedingus.com/forums/thread/1966.aspxhttp://www.medelabreastfeedingus.com/forums/commentrss.aspx?SectionID=14&PostID=1966Replace them when they become damages. Sterilization should be sufficient (whether boiled or in the steam bags) for the hygenic factor.<br />http://www.medelabreastfeedingus.com/forums/thread/1769.aspxMon, 03 Nov 2008 01:05:30 GMTa3cad0db-79cd-4fbb-918f-5e54bdbae2d2:1769mveloccia0http://www.medelabreastfeedingus.com/forums/thread/1769.aspxhttp://www.medelabreastfeedingus.com/forums/commentrss.aspx?SectionID=14&PostID=1769<p>&nbsp;Does anyone know when I should replace my valves?&nbsp; I change my membranes every 3-4 weeks, but I am unsure if I should replace my valves and shields? Thanks </p>