Dating coaches are either scammers or glorified wing persons. I've experienced both kinds. Many are egomaniacs too. Dating dogma says that the highest form of man is the kind who does not care what others think of him. But many of these coaches care a lot what you think of them.
I can not comment much on life coaches because I have never used them. But I expect that most of them would not be able to do such a good job. How many people do you know who have basically figured life out? Very few or none, right? So what are the chances that your next life coach will be competent? That's my logic. For standard generic advice ("don't worry about things that you can't control", "do not succumb to anger") there are plenty of books. In my opinion a coach should be specialized e.g. football coach, music coach. I could be wrong about this because I have never dealt with life coaches. And, bringing it back on topic, do you think that any life coach on Earth is going to have the solution to young hair loss? They'd sooner solve one of the millennium problems!