Last week my sister asked me for a gift idea for a friend who was turning 50.

As I began to brainstorm with her, my thoughts turned to how a person might feel on the occasion of a milestone birthday, whether it be 50, 60, 70, 80 or beyond.

Do milestone birthdays change the way people evaluate their lives? And should we think about this in our gift giving?

Studies show that our outlook on life is affected by milestone birthdays. It is at those times that we take stock of our existence and become more thoughtful about our satisfaction with life.

Approaching a milestone age has recently been shown to drive people toward a search for meaning, purpose and health.

While I’m sure many would enjoy a bottle of wine, a piece of jewelry or a new tech gadget for one these significant birthdays, a more meaningful gift might come from the following categories.

Life purpose. Connecting with and living our purpose is a journey that cannot be forced but typically unfolds. It appears with some introspection, when our eyes and hearts are wide open.

Two books on the subject that make great gifts include Eckhart Tolle’s “A New Earth: Awakening to Your Life’s Purpose” and Rick Warren’s “The Purpose Driven Life: What on Earth Am I Here For?” One of these books along with a note that shares what you find unique and special about the recipient would make a lovely gift.

Leaving a legacy. Legacies leave lasting connections. Carolyn Rosenblatt, author of the blog AgingParents.com, says on this topic: “As people age, they start realizing that it’s not what they have that’s important, it’s who you are and how you interact with the people you love that matters. The idea of legacy becomes ever more important.”

Legacies can be many things— stories, skills passed down to younger generations, financial gifts and so much more. A beautiful book that guides the reader through all the legacies they may have within them is “Legacies of the Heart: Living a Life That Matters” byMeg Newhouse.

Expressing thoughts in words. Have you ever heard your friend say, “Someday I’m going to write a book”? The majority of people who responded to a survey by Brian Tracey, author of “The Psychology of Achievement,” said they want to write a book because they have a message, mission or experience they want to share so others can be inspired.

Someone who has expressed the desire to write—whether a novel, a self-help book, a children’s book, short stories or poems—might appreciate a set of notebooks, a grammar and style guide, and famed horror novelist Stephen King’s “On Writing: 10th Anniversary Edition: A Memoir of the Craft.”

Health satisfaction. Maybe your friend has expressed the desire to get fit. Suggestions among a multitude of choices for the fitness-minded include a water bottle that tracks hydration, a group kayaking experience or a personal invitation to hike all the local trails with you over the next year.

Getting organized. Removing possessions from our lives can reduce our desire for more and help us to find freedom and happiness in owning less. If your friend has expressed a desire to simplify their life, consider getting them “The Life-Changing Magic of Tidying Up,” by Marie Kondo along with a coupon for a day of help purging and organizing their possessions.

Learning a new skill. If your friend has an interest in developing a new talent, you might consider the gift of an expert. Could a favorite local chef spend a few hours with your friend teaching them the fine art of cooking?

Is there a master gardener that would share some of the finer points of a sustainable garden? Would the CEO of a charity be willing to give their time to consult with a friend who is interested in starting a nonprofit?

Putting thought into a friend’s milestone birthday present is a something only you can give. Your gift will be built upon an awareness and an appreciation of their unique interests and desires.

It lets them know you value them and their years on this earth.