I don't really think I had a set time frame. When I noticed I could still express a decent amount of milk after pumping that's when I would try new ones.
The flange part or the membrane? Unless your breasts have changed in size, I would think the flanges wouldn't have to be changed. I sized down from the standard (27 I think) to the 24 after 10 months of pumping but only because my breasts went back to their pre-pregnancy size and a lot more than just my nipple was being pulled in. I also noticed decrease output and longer letdown time until I switched.
The membranes I changed every few months or sooner if I noticed a decrease in suction.
Wow I just realized that I wrote flange but meant membrane!!! <walks away embarrassed>
When I tried to order new valves (the ameda equivalent of membranes I think?) I couldn't find them because I was searching using the word flanges... I ended up googling "white things for ameda pump" and there whey were lol.
Then Comes Family, LLC is a participant in the Amazon Services LLC Associates Program, an affiliate advertising
program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.