You nailed it. Every kid is different, and overtired = not going to sleep. Rituals and good scheduling are where it is at + stupid dumb luck.

Our first, we didn't sleep for like 16 months. It was horrific.

Our second has been great (with a few stretches of waking up (to be expected)). Last week he crawled up the stairs and said "i go sleep" and asked to be put in his crib and laid down and went to sleep immediately. I was just sort of shocked ....