diff --git a/init.el b/init.el
index e47b1ca..da8e3e0 100644
--- a/init.el
+++ b/init.el
@@ -10,6 +10,7 @@
   (package-initialize))
 
 (use-package delight
+  :if (package-installed-p 'delight)
   :demand t)
 
 (setq user-full-name "Evie Litherland-Smith"
@@ -47,19 +48,23 @@
 (scroll-bar-mode -1)
 
 (use-package nerd-icons
+  :if (package-installed-p 'nerd-icons)
   :demand t)
 
 (use-package nerd-icons-dired
+  :if (package-installed-p 'nerd-icons-dired)
   :after (nerd-icons dired)
   :commands nerd-icons-dired-mode
   :hook (dired-mode . (lambda () (nerd-icons-dired-mode +1))))
 
 (use-package nerd-icons-ibuffer
+  :if (package-installed-p 'nerd-icons-ibuffer)
   :after nerd-icons
   :commands nerd-icons-ibuffer-mode
   :hook (ibuffer-mode . (lambda () (nerd-icons-ibuffer-mode +1))))
 
 (use-package nerd-icons-corfu
+  :if (package-installed-p 'nerd-icons-corfu)
   :after nerd-icons)
 
 (setopt mode-line-compact 'long)
@@ -132,6 +137,7 @@
                  (window-parameters . ((no-delete-other-windows . t))))))
 
 (use-package khalel
+  :if (package-installed-p 'khalel)
   :after (appt org)
   :commands (khalel-run-vdirsyncer khalel-import-events khalel-add-capture-template)
   :custom
@@ -157,15 +163,16 @@
   (message-auto-save-directory nil)
   (message-kill-buffer-on-exit t))
 
-(setq mail-user-agent 'mu4e-user-agent
-      read-mail-command 'mu4e)
-
 (use-package mu4e
+  :if (package-installed-p 'mu4e)
   :bind
   (("C-c m" . mu4e)
    :map mu4e-view-mode-map
    ("o n" . mu4e-org-store-and-capture))
   :hook ((mu4e-main-mode mu4e-headers-mode) . (lambda () (visual-line-mode -1)))
+  :init
+  (setq mail-user-agent 'mu4e-user-agent
+        read-mail-command 'mu4e)
   :custom
   (mu4e-read-option-use-builtin nil)
   (mu4e-completing-read-function #'completing-read)
@@ -555,6 +562,7 @@
                       tab-mark)))
 
 (use-package diff-hl
+  :if (package-installed-p 'diff-hl)
   :functions (diff-hl-magit-pre-refresh
               diff-hl-magit-post-refresh
               global-diff-hl-mode)
@@ -685,6 +693,7 @@
   (khalel-add-capture-template))
 
 (use-package org-roam
+  :if (package-installed-p 'org-roam)
   :after org
   :defines org-roam-directory
   :functions org-roam-db-autosync-mode
@@ -723,6 +732,7 @@
 ;;       :target (file+datetree "journal.org" week)))))
 
 (use-package org-journal
+  :if (package-installed-p 'org-journal)
   :after org
   :demand
   :bind ("C-c n d" . org-journal-new-entry)
@@ -799,6 +809,7 @@
   (org-icalendar-combined-description "Emacs org-mode combined export"))
 
 (use-package org-noter
+  :if (package-installed-p 'org-noter)
   :after (org doc-view citar)
   :commands org-noter
   :custom
@@ -813,6 +824,7 @@
   (org-noter-prefer-root-as-file-level nil))
 
 (use-package citar
+  :if (package-installed-p 'citar)
   :defines (citar-bibliography
             citar-indicators)
   :functions (citar-indicator-create
@@ -885,6 +897,7 @@
 (setq org-preview-latex-default-process 'dvisvgm)
 
 (use-package vertico
+  :if (package-installed-p 'vertico)
   :functions vertico-mode
   :custom
   (vertico-cycle t)
@@ -894,6 +907,7 @@
   (require 'vertico-directory))
 
 (use-package marginalia
+  :if (package-installed-p 'marginalia)
   :functions marginalia-mode
   :custom
   (marginalia-annotators '(marginalia-annotators-heavy
@@ -904,6 +918,7 @@
   :config (marginalia-mode +1))
 
 (use-package orderless
+  :if (package-installed-p 'orderless)
   :custom
   (completion-styles '(orderless basic))
   (completion-category-defaults nil)
@@ -912,6 +927,7 @@
                                    (eglot-capf (styles  orderless)))))
 
 (use-package corfu
+  :if (package-installed-p 'corfu)
   :defines (corfu-map
             corfu-mode-map
             corfu-margin-formatters)
@@ -963,10 +979,12 @@
   (corfu-popupinfo-delay 0.3))
 
 (use-package corfu-terminal
+  :if (package-installed-p 'corfu-terminal)
   :after corfu
   :functions corfu-terminal-mode)
 
 (use-package cape
+  :if (package-installed-p 'cape)
   :after corfu
   :functions (cape-emoji
               cape-file
@@ -980,6 +998,7 @@
   (cape-dabbrev-min-length (+ corfu-auto-prefix 1)))
 
 (use-package consult
+  :if (package-installed-p 'consult)
   :functions (consult-org-heading
               consult-history)
   :bind (("<remap> <imenu>" . consult-imenu)
@@ -997,10 +1016,12 @@
          ("<remap> <comint-history-isearch-backward-regexp>" . consult-history)))
 
 (use-package consult-eglot
+  :if (package-installed-p 'consult-eglot)
   :after (consult eglot)
   :bind (("C-c c s" . consult-eglot-symbols)))
 
 (use-package tempel
+  :if (package-installed-p 'tempel)
   :defines tempel-path
   :functions (tempel-expand
               tempel-abbrev-mode)
@@ -1011,6 +1032,7 @@
   (tempel-trigger-prefix "+"))
 
 (use-package tempel-collection
+  :if (package-installed-p 'tempel-collection)
   :after tempel)
 
 (require 'tramp)
@@ -1034,9 +1056,11 @@
          )))
 
 (use-package rainbow-delimiters
+  :if (package-installed-p 'rainbow-delimiters)
   :hook (prog-mode))
 
 (use-package envrc
+  :if (package-installed-p 'envrc)
   :hook (after-init . envrc-global-mode)
   :custom
   (envrc-show-summary-in-minibuffer t))
@@ -1052,6 +1076,7 @@
   (treesit-font-lock-level 3))
 
 (use-package treesit-auto
+  :if (package-installed-p 'treesit-auto)
   :after treesit
   :functions (treesit-auto-add-to-auto-mode-alist
               global-treesit-auto-mode)
@@ -1113,6 +1138,7 @@
   )
 
 (use-package apheleia
+  :if (package-installed-p 'apheleia)
   :delight apheleia-mode
   :defines (apheleia-formatters
             apheleia-mode-alist)
@@ -1129,26 +1155,28 @@
   :hook ((prog-mode yaml-ts-mode) . (lambda () (flymake-mode +1))))
 
 (use-package flymake-shellcheck
-  :disabled t
+  :if (package-installed-p 'flymake-shellcheck)
   :functions flymake-shellcheck-load
   :after flymake
   :hook (sh-mode . (lambda () (if (executable-find "shellcheck" t)
                                   (flymake-shellcheck-load)))))
 
 (use-package flymake-yamllint
+  :if (package-installed-p 'flymake-yamllint)
   :functions flymake-yamllint-setup
   :after flymake
   :hook (yaml-ts-mode . (lambda () (if (executable-find "yamllint" t)
                                        (flymake-yamllint-setup)))))
 
 (use-package flymake-clippy
-  :disabled t
+  :if (package-installed-p 'flymake-clippy)
   :functions flymake-clippy-setup-backend
   :after flymake
   :hook (rust-mode . (lambda () (if (executable-find "clippy" t)
                                     (flymake-clippy-setup-backend)))))
 
 (use-package flymake-eslint
+  :if (package-installed-p 'flymake-eslint)
   :functions flymake-eslint-enable
   :after flymake
   :hook ((js-base-mode typescript-ts-base-mode) . (lambda () (if (executable-find "eslint" t)
@@ -1179,6 +1207,7 @@
     ))
 
 (use-package magit
+  :if (package-installed-p 'magit)
   :bind (("C-c g" . magit-status)
          :map project-prefix-map
          ("m" . magit-project-status))
@@ -1199,9 +1228,11 @@
                             ("\\`\\(?:gitea:\\|gt:\\)\\([^:]+\\)\\'" "git.xenia.me.uk" "gitea.user"))))
 
 (use-package forge
+  :if (package-installed-p 'forge)
   :after magit)
 
 (use-package nix-mode
+  :if (package-installed-p 'nix-mode)
   :mode "\\.nix\\'"
   :functions nix-prettify-global-mode
   :config
@@ -1212,6 +1243,7 @@
   (nix-prettify-global-mode +1))
 
 (use-package lua-mode
+  :if (package-installed-p 'lua-mode)
   :mode "\\.lua\\'")
 
 (defun my/enable-fill-column (col)
@@ -1244,9 +1276,11 @@
   (setq python-ts-mode-hook python-mode-hook))
 
 (use-package python-docstring
+  :if (package-installed-p 'python-docstring)
   :hook python-base-mode)
 
 (use-package python-pytest
+  :if (package-installed-p 'python-pytest)
   :defer t)
 
 (use-package files
@@ -1265,9 +1299,11 @@
   (doc-view-scale-internally t))
 
 (use-package auctex
+  :if (package-installed-p 'auctex)
   :defer t)
 
 (use-package markdown-mode
+  :if (package-installed-p 'markdown-mode)
   :custom
   (markdown-enable-math t)
   (markdown-enable-html t)
@@ -1279,6 +1315,7 @@
   (set-face-attribute 'markdown-comment-face nil :inherit 'variable-pitch))
 
 (use-package pandoc-mode
+  :if (package-installed-p 'pandoc-mode)
   :after (markdown-mode)
   :hook (markdown-mode . conditionally-turn-on-pandoc))
 
@@ -1293,11 +1330,18 @@
   (eww-browse-url-new-window-is-tab nil))
 
 (use-package scad-mode
+  :if (package-installed-p 'scad-mode)
   :defer t)
 
 ;; Scratch buffer shortcut
 (keymap-global-set "C-c w x" #'scratch-buffer)
 
+(defun my/open-init-file ()
+  "Open `user-init-file'."
+  (interactive)
+  (find-file user-init-file))
+(keymap-global-set "C-c w i" #'my/open-init-file)
+
 ;; Org shortcuts
 (defun my/open-org-directory ()
   "Open base `org-mode' directory in Dired."