The worry most people have with this suggestion is that children are going to get discouraged if they fail. But that is not necessarily the case, and I think teachers, parents, and other adults have a great opportunity to help prevent this. If we demonstrate that needing to put down a book for awhile is not a failure, then we can help children become more willing to experiment and to try things which are currently just out of reach.
This is the concept of growth mindset; and we need to teach that to our children in any way possible. It has been shown in studies that growth mindset has a positive causal influence on academic and financial success (I cannot state sources, but I know I've come across this)
Note to self: Research this later.