Protagonists as well as readers learn by exposure to different people, ideas, and locales.
In Murder is Medical, book 10 in the Susan Wiles Schoolhouse Mysteries, retired teacher turned sleuth Susan Wiles teams up with a new friend, and they become two peas in a pod. Both have detective daughters who warn them to stay out of police business, both are grandmothers, and both possess intelligence, curiosity, and gumption. By observing the actions and quirks of her new friend, Susan discovers truths about herself.
Speaking of challenges, in my new release, The Tainted Course, Emily and Henry Fox have recently become parents to a moody, eye-rolling teenager. When their new daughter faces harm, it brings out the wild cougar in Emily and a fiere protective instinct in Henry that throws him off kilter.