For example: Yesterday's picture book about a girl and her imaginary friend did not require research. I wrote from my thoughts and that is it.
Today's picture book required research. I could have done without it but then I might have had an inaccurate character. The story is about a penguin and my friend who loves penguins will know if I write something that is not correct. So, I have done research as to type, location, diet, etc.
Research isn't easy and sometimes it isn't very fun. It depends on the writer, the subject and whether the writer really is interested in the subject. Some people even like research too much. There should be enough time spent on research to have a good, correct story but there is the risk of spending too much time researching. There has to be a limit so that the story can get written.
Today's picture book - Penny the Penguin