Whether the pages, posts of the blog or RSS feed, you can choose to change the number of items you want to appear on the front page of the blog or in your feed. For the posts on the blog index, you have to limit their number if you have long posts to avoid long “scrolls” with the mouse. If your articles are short, or if you use the “read more”, do not hesitate to increase the number of items on the front page, visitors will have a better visibility of topics.
For the RSS, is set as standard on the last 10 items. You can increase it if you want your readers to see more and increase your visibility.