Usually not necessary. But, but and but....(it happened to me!), if the plane is delayed and you miss the connecting flight in Vancouver, you need to check out all your luggages, line up, take your luggages to a hotel and bring them back to the airport the following day........
That was 3 years ago, the plane left Ottawa 2 hours late, and 6 of us, including 3 elderly got stuck at Vancouver. One old couple was even worse, their son/daughter didn't give them any money at all.
Lesson to learn, prepare the best, expect the worst. There are rainy days.......