Let's say you have a homepage where you want to be able to feature 10 posts of various types (posts, pages, and Custom Post Types). You have hundreds of these posts to choose from. What would be the best, most userfriendly way to allow a user to select and sort posts that will appear on the homepage, without using a plugin? The catch is that the publication date is irrelevant, so you might have both very old and very new posts appearing together on the homepage.
You might do this by adding a custom taxonomy like "Featured on Homepage" and then run a query using that taxonomy term. But then what happens when the user adds more than 10 posts to the term? Do you exclude the older posts? Randomly exclude everything after the tenth post? Do you require that the user remove the term from posts she no longer wants on the homepage? Or do you require that the user sort these posts herself, maybe by page order (except some content won't have page attributes)?
It's pretty easy to solve this by using a plugin like Advanced Custom Fields Pro (Post Relationships) or Simple Page Ordering, but I'm wondering if there's a good, user-friendly solution that doesn't require a plugin?