"...highly cost effective."
— Alexander Sawyer What They Say

How can I change the number of posts (or sermons, events, etc.) shown per page?

You can change the number of entries shown per page in Settings > Reading with “Posts per page”. This affects all post types (blog, sermons, events, people, locations), not only blog posts.

If you want to change the “per page” setting on a per post type basis (ie. show 5 sermons per page, 12 events, 10 blog posts, etc.), try the Custom Posts Per Page plugin.