how long to pump?

As a rule of thumb (where ever that phrase came from),
you should pump 15-20 minutes each time. 

I just can't get over how ridiculous the ads for hands free pumping bustiers are. 

I also read that in order to stimulate your milk supply,
you should pump five minutes after your milk stops flowing. 

"I wish I could wear my pump ALL day, I love it so!" It's like they think the pump is their baby in these pictures!

Now I have yet to figure out if that means when your let down stops, or if you actually have to wait until the occasional drops quit altogether. I think that it's somewhere in-between, and for me personally, with the sore nipples that I have been fighting since day one, I usually don't stay on the pump for more than 25-30 minutes. When I start reducing pumps, though, that will need to change.

You should pump the same amount of time every day.

"Oh my goodness! You should totally try this!"

Here's my example. I pump nine-ish times a day for twenty minutes. That's 180 minutes (that's three freaking hours, I know!) So when I start reducing pumping sessions, I will still need to maintain 180 minutes. So for
8 pumping sessions: 22.5 minutes ( think I'll pump for 23 minutes. nbd)
7 pumping sessions: 26 minutes
6 pumping sessions: 30 minutes
5 pumping sessions: 36 minutes
4 pumping sessions: 45 minutes
3 pumping sessions: 1 hour

(remember not to reduce more than one pump per month!)

I doubt that I will get down to 3 for fear of losing my milk supply. I might not even do four. I'm shooting for a year of pumping as much as I can, and then I might still pump --maybe do the 3 a day to get what I can for Miss N so she can enjoy my benefits as long as possible.

I hope this helps!