I suspect this is different for each of us. From my own personal experience, I would say that in general it wouldn't be too personal. Just like talking about experiences (again: in general) doesn't have to be too personal.

Now that I am working on an answer to this request, I'm struggling with the question: just what is too personal? When can something be too personal? I guess people consider something to be too personal when writing about it stirs up heavy emotions, most often being anger, pain or grief. To me that only indicates that you haven't dealt with the experience yet. Just thinking about it still makes you mad or sad and hence too personal.

You may not want to publish it for the entire world to see but from my experience writing about it helps you clarify things. First of all you force yourself to not only think about things, but also give these thoughts structure and perspective. And by doing so, they start to make more sense to yourself as well. As they start to make sense, they also get more in your control. By telling (and reviewing) the story, you can see the correlations and inevitabilities. By getting your thoughts in perspective, you start to see things in perspective. You're getting the experience out of your system. It's a step in the process of converting something that occupies you (albeit not continuously and maybe even not consciously) to a memory, an experience. And as Huxley already said: "Experience is not what happens to you. It is what you do with what happens to you."

Reading about other people's similar experiences and how they dealt with their issues can be very helpful. When reading the stories of others you realize that you're not the only one. In many cases you can even come to the conclusion that (knowing how bad others have had it) your own situation is not all that bad after all. There are people who have been hit by life even harder than you. It helps you put things into perspective. And you can learn from both the positive effects and the mistakes of others.

One precondition when publishing your experiences with the intention to help others is that you don't put any judgment into your story. What worked for you may not work for others. There's no such thing as "the right and proper way".