Again this is a matter of choice. I may not use the same kit for each page; but I do try to use complimentary kits. Let's take my Atlanta aquarium layouts. I have used "A Fish Named Ernie" by Spinkydink Designs, "Fishy Fishy" by Connie Prince, as well as "Squid Ink" by Creations by Rachel & Late Night Scraps. All of them have similar colors and theme going on.
On the same day, I have also scrapped packing up and leaving. For those layouts, I have used different kits than from the aquarium. Each of these have similar colors and styles.
Personally, I feel if you are making a series of layouts for a trip, birthday, special event, that just one kit will severely limit your choices. If you find several kits with complimentary colors and theme, then you can mix and match elements and papers.
I would be interested in hearing what you think.
Fishy Fishy (c)Connie Prince; Sealife (c)FabaScrapDesigns
Template by Amy Stoffel; Kraft Again alpha (c)Etc. by Danyale
Word art (c)Word Art World by Jennifer
Font: Century Gothic