I have read some and I believe they helped me in some way. They will not change your life immediately after, as if you had just discovered the secret of a good life, but some of the messages and advices might stick to you in a way you will start to implement them in your life, slowly improving some aspects of it. In an almost unconscious manner.

But I would recommend to take a look about the author first. The ones that helped me the most were from people who had a backstory that felt legit and that I could connect to some extent.