Disclaimer: This is going to be colored by my personal experiences...
I'm impressed if someone breastfeeds or pumps for a year. It has been a struggle for me to get this far. Hell, I applaud anyone who makes it to their goal, be it six weeks, six months or six years.
We have had to supplement from six days old (valid and necessary...no flames please...we tried EVERYTHING, and, after reading another post and seeing some photos, I suspect I may have type I tuberous breasts, but I need to research that more...just a lot of physical and breastfeeding problem coincidences). I bought a double electric pump. Well, of course, after the supplemental bottles, my daughter liked them MUCH more than Mommy's breasts (I have slow let-down, and really, why would you suck for two minutes for a little bit of milk when you could get as much as you wanted immediately). She weaned herself/rejected the breast at three months from nursing.
She's almost ten months, and I continue to pump, pumping every 3-4 hours. I get about 10-12oz a day. The MOST I ever got was 14oz, and that was pumping for 30 minutes every hour, on the hour, round the clock, which, I'm sorry, is NOT feasible for me for more than a couple of days of insanity.
At one year, I WILL cut down to twice a day, and then reassess my goal. The "stress" (not exactly, but I guess that's a close enough approximation) of ALWAYS, at a certain time, having to be home or have the pump with me, making sure I have batteries (if I'm in the car), etc. wears on me. Maybe I'm selfish; fine. I have had the choice from day one to go completely to formula which may have been more convenient, which may have been easier. I could have starved my child to fulfill my need to be "the perfect mother" (it was actually my very crunchy, pre-schooler-breastfeeding best friend who brought me to my senses on this one), which, obviously, I wouldn't do. But, in the end, I made the choice to try for six weeks. And when I got there, I went for three months, and she weaned, so, it was exclusively pumping then...then six months (the new year...very convenient)...then nine...now I'm shooting for twelve. But, to be honest, I'm very worn out on the whole pumping thing. And, according to kellymom.com, only 17.2 percent of babies are getting ANY breastmilk at twelve months...so, I'm okay with scoring an "83%" or whatever on this issue.
I don't think it's good to SUDDENLY stop and just tell the baby, no more!, ...but, if a mother wants to implement gradual weaning, even if parent led (it's supposed to be MUTUALLY desired), I'm not going to villify her for her choice. I don't have a problem with people breastfeeding when their child's a pre-school, I don't have a problem with people decidingto stop if they feel it's time. There are many ways to nurture you child, and breastfeeding is only one of them.