When I first started scrapping I did only double page LOs. I just couldn't do a single page. Eventually I moved onto single pages and I do them most of the time now it seems. It is really determined by the number of pics I want to put on the pages.
I try to use coordinated paper with pics from the same event or time. For instance, I did three pages on a day at the park with my grandsons. I used some of the same print papers and colors on all three pages to pull them together and put them in sequential order in my album. Does that make sense?