I have interviewed for hundreds of positions and have never received a thank you letter. I would consider a hire at a grade higher, given they're grasping what

I have interviewed for hundreds of positions and have never received a thank you letter. I would consider a hire at a grade higher, given they're grasping what in hindsight would be basic relationship building skills. I would consider recommending the candidate to a friend if they were otherwise unsuccessful. But don't be insidious. You're cultivating a relationship and have already met in person, not selling a connection via LinkedIn. A simple message is fine, written semi-formally. If I was interviewing for a party on the beach 'Hey Dude!' might work, but I'm not, I'm interviewing for a serious job that involves serious decisions and some level of tact. 'Hey Dude!' doesn't do that. Nor does 'pls' or 'thx' as it leads me to assume someone is so busy with their life attending interviews they're too busy to type 'e' 'a' or 'n' and would not be interested in a further job to add to their schedule. Sending more than one mail may also imply a level of desperation. If having heard nothing for a week perhaps the interviewer doesn't share your level of conscientiousness and their position best skipped for someone able to reply to emails. I also wouldn't handwrite it, unless a physical personal touch was make-or-break. I doubt any hiring manager would not smile seeing a short proactive message in their inbox the day after an interview. [I did receive, at the end of the interview, an invite to a Halloween party. She became a fantastic member of the team. I don't recommend Halloween party invites a solid interviewee strategy, however.]