We started co-sleeping with our now 4 yr old just before he turned 3 because of nighttime seizure issues. Before that, we had used the Healthy Sleep Habits methods and he was NEVER a very good napper and nighttime we THOUGHT was ok. Turns out that once we started co-sleeping we realized that his nighttime sleep was very disturbed (in part due to the seizure issue). It's amazing how much you don't know what's going on when you are not in the same room/bed!
Well, I started co-sleeping with my now 2 yr old since birth and it has been a MUCH better experience. Did not set out to do it past infancy but I honestly don't want to stop (unless he leads it) and he loves it. He's much more trusting, independent, and starting talking much earlier than my first son. He also sleeps later in the morning which my first son never did because he was always fussing in the morning. What a wonderful way to wake up, with a loving parent next to you (and vice versa)!
Although we are still co-sleeping at this age, I do have a circle of friends that co-slept and their older children have moved on to sleep independently when they were ready (usually school-age, 7-8 yrs old). No one has had to push the kids out of their bed as some people would have you believe.
Best of luck to you and enjoy those precious moments of cuddling and more sleep!
Karen C.