Sorry...never had one.
Me either.
I'm mostly of the opinion that books, coaches, videos and the like don't readily help a player improve much. The thing that helps the most is basically hard work. The more you like chess the easier the work is to bear (and if you're in love/obsessed you can study like Fischer, every waking hour). But to me it's mostly being willing to put in the hours... not all of them fun.
But... like you said guidance from a real person on your specific needs can be very helpful as well as encouraging. If you haven't gotten far on your own, even if you're still a beginner, getting a coach may be the way to go.
What I've liked about talking with stronger players is the practical POV. Sure a database can tell you the most common move and give you percentages, but noticing your style a person may suggest a different line. Or a lesser tried but strong line. Things like this are valuable.
Sorry I couldn't answer your question though
I have been teaching both group and private music lessons for 25+ years and know that nothing beats private lessons. Also, after easily spending too much money on golf videos, books and training aids, again, nothing beats private golf lessons. My golf score dramatically improved after only three lessons from a golf pro.
Please share your experiences from private chess lessons - the number of lessons, the interval between lessons (once a week, once a month), the improvement gained after the lessons, the cost per lesson, the experience level of your teacher, what surprised you the most after the lessons, etc. Thank you.
Last, as an adult, is it better to wait until one reaches a certain rating before spending money on private lessons, or not?