I'm just beginning to look into purchasing a breast pump. This may sound like a silly question, but why would a person only want a single pump? Wouldn't it be more efficient to use a dual pump?
Also, what about the manual pumps...wouldn't your hand get tired?
Pardon my ignorance!!

Re: One pump or two?
Depends on your circumstances, really. If you're going back to work, you want a double electric. If you're a SAHM who will only need an occasional bottle, a single manual is fine (why spend the $ on something you don't need?).
I've used both (I'm a working mom). The manual doesn't really hurt, actually.