it depends on the kit.
For larger kits and what I am scrapbooking.
For example if I have a lot of pictures from a party or vacation I like to use a kit that has lots of papers so I can make as many pages as needed from the same kit.
If I am scrapbooking some "everyday" moments, I might use a smaller kit and only make one page from the kit. Although I do have some favorites that I will use again and again.