My wife and I worked very hard to create an effective bed time routine for our son and just as hard to maintain it. We have tweaked it a bit to accommodate for our son growing up and his needs changing, but overall the foundation has remained the same - dinner, bath, book, bed.
We learned just last night how effective our routine has become. As it is summertime, we are able to get our son into the pool (which he loves). Generally his naps after swimming are lengthy which ever parent relishes. Yesterday's after swim activities largely mimicked his bed time routine in hind sight. He had a large snack after swimming, read a book, then went down for a nap. We were expecting about 2 hours give or take, which is typical after he swims. It wound up being 4 hours and we figured out that he thought it was actually bed time. We had no choice but to change his diaper (was not in his usual nighttime diaper) so we had to get him up. We were hoping that it would be like a normal midnight change where he would barely be awake then go right back to sleep. Last night, however, we were not so fortunate. He was wide awake and hungry (which was understandable) so it became a bit of a trying to time get him a snack then get him back to sleep. He did go back to sleep and was down for the rest of the evening.
What we learned from last night's events is that we have gotten him into a very effective night time routine. We have implemented it since birth and have continued it ever since. He is comfortable with his routine and his body inherently knows what all of the steps put together mean. We encourage any parents, or potential parents, who ask us to get their child into a consistent routine. It helps the child and it helps the parents. While last night was a bit difficult, it validated our efforts.