With my daughter, my original target was 6 months. But when I got to six months, she still seemed so little and it was so easy, that I set another target for a year. At a year... LOL she STILL seemed so little, and it was still so easy, so I said 1 and a half. When I got there, I said 2. She self weaned at 21 months, which I think was quite a good age.
So for my next baby, I plan to feed until about 21 months for equality! I don't think I want to go over 2, because I think it'd be a battle with lots of tantrums to try and stop after that if the baby didn't want to self wean.
It's been so nice to have my boobs back to a normal size and wear underwire again... another reason I don't want to go over 2 years with the next baby.