2) Are some types of knowledge more useful than others?

To recap what knowledge is, let’s say that it’s information/facts and theories that I’ve formally learned. But it is also information that I’ve gleaned from personal experiences and others’ about the world, others, and myself. In this sense, knowledge has a limited definition to what I know.

Now to the question, are some types more useful than others? What are the types of knowledge? I’m limiting it to what I know. In that definition, there is personal knowledge gained from experience and reflection. There is knowledge about the world gained from learning facts with loads of evidence and sources, and there is some gained from theories with more supporting evidence than contrary evidence.

Is “useful knowledge” knowledge which helps me understand the world better or is it unequivocally true? I have some knowledge that is more qualitative or subjective than other knowledge, but I still find it useful in understanding the world, even if I need to update this information and my understanding of the world at a later time to reduce cognitive dissonance or try to just update or expand my understanding.

Furthermore, I think a lot of knowledge is only relatively true. For example, the fact that all humans are mortals is only a truth so long as we don’t have a way to stave off death. Once we have a computing, engineering, or medical solution to death, then this will no longer be an axiom.