I'd disagree, respectfully. I think it is more common to simply say "I know from experience", unless you are in a formal sentence. If you are on the streets or very casual, you can even say "trust me, I know" which carries the connotations that you DO know from "personal" experience, but without you having to clarify it.

We typically say that someone "knows from personal experience," but it is important that the person actually had the same or similar experiences for this to be a true sentence. So, for example, you could only say, "I know from personal experience that it is difficult to walk on the surface of the moon" if you were one of the Apollo astronauts who actually did this!