We learn the value of things as we grow. As a child that perspective is missing. For example, coloring on a wall, a grown up thinks 'oh man! It's going to cost me X dollars to clean this up or eventually have to repaint this whole room which is going to cost me Y dollars', but a child is thinking 'dad said I can draw, what's the difference between drawing on a paper vs drawing on a white wall?!'

And value is always relative. I give my son a scotch tape, scissors and paper and he gets into a zone - starts drawing, cutting, coloring and of course sticking his artwork on any wall that he wants to. Recently he saw a steel measuring tape, the kind that can be pulled out and after use it retracts into its shell. He wanted to make a model of that. He came back with a paper cut to resemble the shell, and then for the steel tape itself, he cut a big length of scotch tape and stuck it to the shell. I saw it and my grown up brain kicked in, I said 'why did you use the tape for this purpose, you could have used a thread (because thread is cheaper than the tape and the purpose of the tape is to stick things) to show the steel tape', he just said 'why'. I started to explain and I realized, it's the knowing cost of things and tradeoffs and purpose of things - it's a lot. Rather, I just let him enjoy his childhood. :)