I used to write in courier but now I write in TNR. When I have converted manuscripts I loose page count. I'm not sure why so it is now confusing when one talks about page or word count for a novel. Now I go by computer word count instead of multiplying 250 by the number of pages.
For digital publishing, again one has to go by what the publisher needs. Digital readers do not have pages. So when I submitted to BookBaby, I took out the pages, header information, put in Table of Contents by Chapter, About the Author, Title Page, and disclaimer page. The e-publisher links the Chapters in The Table of Contents to the Chapter in the book. They also required paragraph formatting and not Tabs for indenting paragraphs.
For poetry, short story, essays, etc. same advice applies. Check the submission guidelines for the agent, publisher or contest you want to submit to. Good luck!