The Concept of Practical Knowledge

I wonder if we could ask about some other class of things, whether we can distinguish the practical from the non practical. We don't want to organize all the things in the department store that you will happen to find useful. The same piece of knowledge might be applicable to somebody else, one person not so applicable by someone else. And so we shouldn't talk about whether knowledge in general is practical, we should talk about whether it's applicable in some situation by some particular person.