As an employer (and thus an evil capitalist pigdog etc.) I’ve always applied the rule of the thumb that “twice the holiday duration as notice” is polite to the employer and your colleagues who will cover for you - so two days notice for a day off, two weeks notice for a week off, a month’s notice for two weeks off, etc.

“Polite” does not mean “mandatory” of course - circumstances can dictate that sometimes you have to break the rule of thumb and that’s fine.