Last August, after my first round of chemo, I asked my hair stylist, Tammy, if she would make a house call to shave my head since I was already losing my hair. I'm a pretty open book about most things in my life, but for some reason, shaving my head in public just felt too hard.

Shaving my head in general, felt too hard.

After sweeping up the pile of hair on my floor, I immediately put a hat on, and spent the rest of the day avoiding my reflection.

Whether it was dodging the mirror while brushing my teeth, or ignoring my appearance in a window, it was about three weeks before I was no longer jolted by my bald head every time I looked in the mirror.

My dad appreciated my bald head so that we could twin.

As it turns out, Dr. Maxwell Maltz, a plastic surgeon in the 1950's, noticed a pattern in his patients; that it took most of them about 21 days to get used to a nose job, for example.

Similarly, he noticed that if a patient had a limb amputated, it took about 21 days before adjusting to their new reality.

But Dr. Maltz actually took his observation a step further, writing a book where he stated that "it requires a minimum of about 21 days for an old mental image to dissolve and a new one to jell."

This concept was eventually shortened to, "it takes 21 days to form a new habit."

Sound familiar?

The thing is, while it took me a few weeks to adjust to my appearance, it was at least two months before I stopped the automatic process of putting shampoo in my hand every time I got in the shower.

That habit took much longer to untangle.

When you are in the business of behavior change, it's not common to ask how long.

How long until I see results?

How long until this new way of eating sticks?

How long until getting my workouts in every week just feels routine?

On average, according to a study from 2009, researchers found that it takes 66 days before a behavior becomes automatic. That's the average. It can take anywhere from 18 days to 8 months to build new behavior into your days.

How long it takes a new habit to form can vary widely depending on the behavior, the person, and the circumstances though, which is why I love this quote I heard recently on Instagram "change happens small until it happens big."

It's the tiny little things - the micro-actions that you take everyday; subbing a salad for fries at lunch, taking the stairs, getting up and stretching every hour; those actions might not seem like big deals in the moment, but they are laying the groundwork for improving your quality of movement, increasing your cardio capacity and getting more nutrients into your system.

If you've followed my work for any length of time, you know I am a big fan of starting small. Some people look at a 10 minute workout and say what's the point?

The point is that change happens small until it happens big.