Do you have to put last names on mail

In the United States, the United States Postal Service (USPS) does not require last names on mail, but it's generally considered good practice to include them for several reasons:

1. Accuracy: Using both first and last names helps ensure that mail is delivered to the correct person, especially in cases where multiple individuals share the same first name.
2. Efficiency: Including last names can reduce the likelihood of mail being misdirected or lost, as it provides more specific identification.
3. Professionalism: Using both first and last names is a common practice in business and professional settings, and it's often expected in formal correspondence.

That being said, there are some exceptions where you might not need to include last names on mail:

1. Informal correspondence: If you're sending mail to a friend or family member, you might not need to include a last name, especially if you're familiar with their full name.
2. Local mail: In some cases, local mail carriers or delivery services might not require last names, especially if they're familiar with the recipient's address and identity.
3. Special circumstances: In certain situations, such as sending mail to a government agency or a business, you might not need to include a last name if it's not required by the organization or if you're using a specific format (e.g., a government ID number).

In summary, while it's not strictly necessary to include last names on mail, it's generally a good idea to do so to ensure accuracy, efficiency, and professionalism.