One common situation is introducing an invited speaker at a conference. After the first mention, you refer to the speaker using a mix of pronouns and names. Full name or last name would sound weird. Using first name works if the speaker is your friend and many people in the audience also know them as a person. Otherwise "Dr. Lastname" is a reasonable choice.
Academic websites are full of short biographies of speakers, lecturers, PIs, and so on. They are often written in third person. Again, "Dr. Lastname" is often the form of reference that sounds least weird.
Academic spam is often addressed to "Dr. Lastname", especially if the sender is asking the recipient to do something. Using "doctor" as a title is a safe default choice. It sounds respectful, it's very likely to be correct, and it saves the sender from guessing the gender (and possibly marital status) of the recipient.
One common situation is introducing an invited speaker at a conference. After the first mention, you refer to the speaker using a mix of pronouns and names. Full name or last name would sound weird. Using first name works if the speaker is your friend and many people in the audience also know them as a person. Otherwise "Dr. Lastname" is a reasonable choice.
Academic websites are full of short biographies of speakers, lecturers, PIs, and so on. They are often written in third person. Again, "Dr. Lastname" is often the form of reference that sounds least weird.
Academic spam is often addressed to "Dr. Lastname", especially if the sender is asking the recipient to do something. Using "doctor" as a title is a safe default choice. It sounds respectful, it's very likely to be correct, and it saves the sender from guessing the gender (and possibly marital status) of the recipient.