EditorConfig

As a big believer in both consistency and individual autonomy1, I consider EditorConfig an important part of projects’ standard setup:

# https://editorconfig.org

root = true

[*]
charset = utf-8
end_of_line = lf
insert_final_newline = true
trim_trailing_whitespace = true
max_line_length = 80
indent_style = tab
indent_size = 4

[*.md]
indent_style = space

[COMMIT_EDITMSG]
trim_trailing_whitespace = false
max_line_length = 72
indent_style = space

NB:

• While line length is capped at 80 characters here, I typically use a more lenient 90 characters for automated tools (i.e. linting and formatting).
• Naturally, I advocate using tabs by default.
• Strictly speaking, indent_size = 4 invalidates the “tabs can be configured” argument (as pointed out by mkhl) – including it here is a pragmatic compromise; YMMV.