Are post-interview thank you notes absolutely required? No. Neither is brushing your teeth before the interview, that doesn't mean it's a good idea to forgo either.
In this recent piece from CGMA Mag (I know, I know), Ken Tysiac discusses the importance of the thank you:
Candidates should display their gratitude for the interview and interest in the position with an email thank-you note on the day of the interview or early the next day, said Beth A. Berk, CPA, CGMA, a self-employed, independent recruiter based near Washington, D.C.
Following up with another note in the mail also is a good idea, according to Berk. The note that’s sent in the mail can be handwritten, but only if the candidate’s handwriting is neat and legible, she said. Otherwise, a typewritten letter of thanks that includes the candidate’s signature should be mailed as a follow-up.
Berk said employers who use her services have told her that they have been surprised when high-calibre candidates haven’t communicated their thanks for the interview.
“I’m a big fan of thank yous,” she said.
The article notes that if you write like a 5 year old who lost a few fingers in a tragic Big Wheel accident, you should probably send a typed note (regular mail, ya dig) and just slap your signature on it.
For those of you who have dabbled in hiring, just how important is the thank you, anyway? The jury is still out on the matter.