At 6 months, I was pumping four times a day. Generally early morning, once at work, once when I got home, and once later at night.
If you pump less, you may initially get larger volumes at each pump, but you will downregulate your milk supply and ultimately get less.
Yes, unless you are getting sore, pumping after the first let down is finished will help keep your supply up. You may also get another let-down.
I also got 3-6 oz each pumping session. I barely made it to 11.5 months. Everytime my supply dropped, it seemed like we added another meal and needed less milk. But, I used up the last frozen right at 11.5 months. We just switched to cow's milk at that point. I stopped pumping at that point, but kept breastfeeding until age 3.

Pumping will help keep your supply up, yes.

It's been years (YEARS), but I returned after six moths and I think I pumped three times a day initially. Did this in lieu of lunch and explained to my boss at the time (a smoker) that it was no more time than lunch and smoke breaks.

I just returned to work after a 6-month maternity leave. I'm wondering at 6 months out how many times a day people are pumping, and for how long? Right now it seems like I have to do 3 or 4, and I get between 3 and 6 oz. each time. Is that going to be enough? If I pump less, will I get more?

Another question, is it worth keeping the pump on for a while if nothign is coming out (does this help to make more milk)?

Any info appreciated, thanks.