Acording to wikipedia, diaries are almost 2000 years old. And they still work just as well today! At work I have been keeping a simple diary in the form of a giant org document. It’s a practice I have been doing for 9 years and would not be without. While org mode can do a million things, I almost use none of the functionality. Instead the main function I use is the ability to search anything instantly. I use it as for todos, for saving SQL queries, code snippets, for links and in general for things I need to find again. I have a key binding to enable F9 to insert the current date and then I use tags to split things into topics.
(define-key global-map (kbd "<f9>")
'(lambda () (interactive)
(when (eq major-mode 'org-mode)
(org-insert-time-stamp nil t nil)
(insert " ")
)))The only extra module I have installed is org-bullets.
I store the file in git and just do commits regularly. Over time I split out the oldest entries into seperate files, keeping only the latest 3 years in the main file.