One of the side effects of how I use Vim is a lot of buffers are opened. I'll make some edits, then switch to a new file, keeping the buffer open, either in the background or foreground.
Once they start piling up, it's a paid to open the buffer list, navigate to each buffer, and close them all. I thought there had to be other people with this problem and found a plugin that takes care of it for me.
close-buffers.vim give me the ability to interactively select buffers to close, close all hidden buffers, and several other options.