“I wanted to let you know that I have found a new - and very good - home here. I think it's fair to say that I am about as happy as the law allows. I also wanted to let you know that I got the job largely as a result of the resume and LinkedIn profile you helped me construct. I have to say that one of the other things that helped me was my attitude.
Thanks again for all your help. I fully expect that this job will last me into retirement. (I'll be 66 in just over two years and if I end up liking it as much as I think, I may well continue working a reduced schedule past then.) From what I can see now, it looks like I'll be living the good life for the foreseeable future."