Comment by strogonoff

There are ways for not closing HTML tags to backfire in some scenarios.

Some rules of thumb, perhaps:

— Do not omit if it is a template and another piece of HTML is included in or after this tag. (The key fact, as always, is that we all make errors sometimes—and omitting a closing tag can make an otherwise small markup error turn your tree into an unrecognisable mess.)

— Remember, the goal in the first place is readability and improved SNR. Use it only if you already respect legibility in other ways, especially the lower-hanging fruit like consistent use of indentation.

— Do not omit if takes more than a split-second to get it. (Going off the HTML spec, as an example, you could have <a> and <p> as siblings in one container, and in that case if you don’t close some <p> it may be non-obvious if an <a> is phrasing or flow content.)

The last thing you want is to require the reader of your code to be more of an HTML parser than they already have to be.

For me personally this makes omitting closing tags OK only in simpler hand-coded cases with a lot of repetition, like tables, lists, definition lists (often forgotten), and obviously void elements.