Are thank you notes a lost art? Not at all!
If someone has done something special, or given you something of value (whether you wanted/like it or not), it is always appropriate to send a thank you note.
For job interviews, an emailed thank you note should be sent within 24-48 hours, as hiring decisions are often made quickly (though following up with a handwritten note is certainly a nice gesture as well). In addition, be sure to send a separate, individualized email to each person with whom you interacted.
For most gifts, notes should be handwritten and sent within two weeks, though you are granted a little leeway (4-6 weeks) if the gift is for a wedding.
Finally, for other special favors, invitations, or gifts – two weeks is acceptable, but one is better. On this final point, I often get questions about what is a special favor...the answer is anything that someone took extra time to do for you (yes, even if it's 'part of their job'). It's never bad form to be appreciative of someone else's time/efforts/sacrifice!
Thanks for sharing the timelines associated with different situations!
Over the years, it’s been imperative for me to get a business card from each job interviewer (or at lease write down their full name and remember the mailing address so Incanntry mt beest.
Sending each interviewer a handwritten, personalized thank you card after a job interview has always been a game changer for me.
If I have to travel outside the local area for the interview, I make sure to have some blank cards, pens, and postage stamps in the car with me so I can write and mail my card at their local post office to ensure it arrives much quicker than if I mailed it out…