Since I started to use emacs I had to configure it to my likings and needs. Sometimes variable customization is enough but I also rely on many different modes and non-customizable behavior that I have to write elisp.

The biggest improvement to my init.el file and sanity has been the use-package package and macro. use-package allows me to specify what I want out of emacs packages with a simple macro without having to think much but at the same time I longed for the same ability with builtin packages. I only ever saw examples of use-package in combination with third party packages but once I started looking at builtin packages everything fell in place and started using it with every package I could think of.

The most important difference between builting package and third party packages is that the emacs package manager (package.el) does not work with builtin packages. This means that we have to make sure to use :ensure nil when using the use-package macro.

Passing :ensure nil to each expansion of use-package makes sure to disable the default behavior where package.el is used to load the package. As this becomes quickly kind of boring you can customize use-package-always-ensure to make it either t or nil depending on the amount of builtin packages vs third party packages you use.

This is an example from my config where I use use-package to configure some variables and set some hooks for builting packages. I find it is easier for me to read the init.el than the customised variables file so I started keeping most of my customization there.

(require 'use-package)
(use-package
  :custom ((use-package-always-ensure t "Default :ensure to t in `use-package'.")))
  
(use-package display-line-numbers
  :ensure nil
  :custom ((display-line-numbers-type 1 "Relative line numbers.")))

(use-package compile
  :ensure nil
  :custom ((compilation-scroll-output t "Scroll compilation buffer.")
	   (compilation-always-kill   t "Do not ask for confimation.")))

(use-package files
  :ensure nil
  :custom ((make-backup-files nil "Do not make backup files on save buffer.")
	   (auto-save-default nil "Do not auto-save of every file-visiting buffer.")
	   (create-lockfiles  nil "Do not use lock-files.")
	   (require-final-newline t "Ends file with a newline."))
  :hook (before-save . #'delete-trailing-whitespace))