This article is from the Breast Pumps FAQ, by firstname.lastname@example.org (Beth Weiss) with numerous contributions by others.
I own a manual breast pump and use an electric pump at work (the
electric "base" is provided at my workplace!). I actually like my
manual pump, though I have never used a battery operated pump. When I
have a good letdown, I can get 3.5 oz (the capacity of the container)
in just a few minutes. Normally, however :), it takes closer to 10-20
minutes. I have a model from Sears that only cost $11, so I ended up
buying two. It looks like a tall, thin, beaker with a close- fitting
tube (topped with a breast cone) inside of it. My advisor from
nursing mother's council recommended against getting any manual pump
with a flexible "breast cone" (because it makes it harder to get a
good seal) or with "bicycle horn" pumper (because it's hard to get
really clean and it can physically harm you).... For me, I need to
pump regularly in order to maintain my "skill" with it. I used to use
my manual pump every night (when my son gave up his 2am feeding, I
used to still wake up, so I started pumping that milk). When I
started sleeping thru that (and woke up with very full breasts, but
also, an accomodatingly hungry baby!), I didn't have to use that pump
any more. When I *wanted* to use the manual pump, it took me some
time to become used to it again (and, consequently, to get a "regular"
amount of milk from pumping). Also, when I first started pumping, I
only got a miniscule amount (< 10 ml) and it hardly seemed worth it.
In reality, I was not getting a letdown; with practice, I can now get
3-6 oz per pumping session. Your mileage may vary.