It's adviced to replace the Original Diaphragm, Flange and Duckbill Valves every 3 months, and replace the Milk Container every 3-6 months. Subscribe and Save: Get replacement parts delivered every 3 months with 15% off discount. Cancel anytime. Accessories Included: eufy Breast Pump S2 / S2 Pro Milk Container (5 oz, 2-Pack) x1 eufy Breast Pump S2 / S2 Pro Double-Sealed Flange (27 mm) x1 eufy Breast Pump S2 / S2 Pro Duckbill Valves (4-Pack) x1 eufy Breast Pump S2 / S2 Pro Diaphragm (2-Pack) x1 Note: The eufy Accessories Subscription Service requires a monthly, quarterly, semi-annual, or annual subscription fee (depending on the service duration you select). Your subscription fee will be charged on the date of your first purchase and will begin a term. We will deliver accessory package items on a monthly, quarterly, semi-annual, or annual basis, depending on the service duration you select. You can cancel, suspend, or restart the subscription service at any time after purchasing the service.