When to use a period:
* When "Dr." is used as a title before a name: Dr. Smith, Dr. Jones, etc.
* When "Dr." is used alone as an abbreviation: She's a Dr.
When to omit punctuation:
* When "Dr." is part of a longer title, such as "Dr. med." or "Dr. rer. nat.": Dr. med. Müller, Dr. rer. nat. Schmidt
Important Notes:
* Formal vs. informal: In very formal writing, like scientific papers or medical documents, you might see "Dr." without a period.
* Consistency: Stick to one style within a single piece of writing.
Example:
* Formal: Dr. Smith, the renowned physician, will be presenting at the conference.
* Informal: My friend is a Dr.
Let me know if you have any more questions!