I used Ameda for my 1st baby 2 yrs ago and also for my 2nd baby now. According to my experience, you need spare 替換漏斗 ... it is sold at around$70 in HK but it is very cheap in US/UK. I bought it @UK$3 for 2-3 pieces (I can't remember). I used the pump for 1 yr and only need to replace the valve. Others parts are still working.
Yes, no need to steam 筒形過濾膜 coz it is not in contact with milk. Just rinse it with hot water before use. In fact, the distributor in HK said it is no need to steam the valve but I steamed for my 1st baby....maybe that's why I have to replace it. Now, I don't steam the valve but remember to put it in hot water immediately before and after use. If you rinse it with cold water after pumping, milk would stick to the interior of the valve and it is difficult to clean it afterwards. I tried to put it in hot water again several hrs later and found that I still can't clear the milk mark on the valve....