When should you capitalize the word 'day'?

When should you capitalize the word 'day'?

The word 'day' should be capitalized in the following instances:

1. At the beginning of a sentence: "Day after day, the sun rises in the east."
2. When it is part of a proper noun or a specific event: "Independence Day," "Christmas Day," "New Year's Day."
3. When it is used as a title or a name: "Father's Day," "Mother's Day."
4. When it is used as a proper noun in a specific context: "The Day of the Dead," "D-Day."
5. When it is used as a proper noun in a religious context: "Easter Sunday," "Good Friday."

However, in general, the word 'day' is not capitalized when used in a regular, non-specific sense: "I had a busy day at work."