It seems to me that frequently, to realize that your resources in a domain has improved, you need to heavily risk the very few resources that you know you have.
In the example the author gives, her husband did not have that inaccurate, yet reasonable perception, and only in hindsight does the author realize her own inaccurate perception.
I cannot recommend that readers take the author's advice to heart as carelessly as she presents it. There is some merit to it, but there are sometimes real consequences when you try when your perception was accurate that you shouldn't have, and you have carelessly misread your increase in capacity, especially if you are desperate for it.