Business Insider asked etiquette experts when it's appropriate to send a handwritten thank-you note. They said a note is essential after staying at someone's home or receiving a personalized gift.

I realize that the concept of mailing a handwritten thank-you note after a job interview sounds really old-fashioned. But I still believe that sending such notes – even to an avatar – conveys more ...

Dear Eric: Last August, my husband and I told his niece that we would help with her daughter’s college expenses. We sent $2,000 to the college for the first semester. We received a thank-you text from ...