My father-in-law retired at 55 and is now 86. His successful early retirement taught me 4 lessons I plan to follow.

• My father-in-law successfully retired early at 55 and I hope to follow in his footsteps.
• Like him, I want to have several investments and own my home outright before I retire.
• He's also inspired me to stay active, find hobbies, and strengthen my relationship with my spouse.

My father-in-law, Frank Noble, retired at the age of 55 after a successful career in forestry in Australia.

At 86, he's now been retired for roughly the same amount of time as he worked. He said that if given his time again, he'd still follow the same path and choose to retire early.

After chatting with him about his decision, I learned key lessons I plan to follow now that I'm 40 and working to plan my retirement.

Own your home outright and have several private investments before retiring

One key thing that made Frank's early retirement much easier was that he owned his home outright before he retired.

He sold his family home in Tyers and bought his current place — a more affordable one in Bright — in cash so he didn't need to take on a mortgage.

My husband and I would like to be in the same mortgage-free position by the time we retire.

We currently have two investment properties that we're paying off, and we may sell one or both in the long run in order to pay for our future "forever" home in cash.

Frank also attributed his successful retirement to having private investments on top of his pension. We've also started investing in shares and reinvesting the dividends in order to build long-term wealth.

Stay active

My father-in-law is extremely fit, and people often remark that it's hard to believe he's approaching 90.

At 86, he still goes to the gym three days a week, spends hours in his garden each day, and chops all of his own wood for the winter months.

All in all, he just stays moving. I was reminded of Frank recently while reading a great book called "Ikigai: The Japanese Secret to a Long and Happy Life."

In it, the authors talk about how water moves and is at its best when it flows and doesn't stagnate, and how the human body is the same.

That analogy resonated with me and reminds me of Frank: As you age, it's important to keep moving each day in order to keep your body running for a long time.

I plan to follow his lead and focus on working out and staying active as I age — if I can stay in good health, retiring early will be far more enjoyable.

Have hobbies that inspire you

My father-in-law found joy in gardening, going to the gym, and playing golf when he retired. He's also travelled with my mother-in-law throughout Australia and overseas.

Frank said all of these hobbies and passion pursuits have given him a much-needed sense of adventure and purpose in retirement.

It's inspiring that he follows his passions and I feel lucky that one of mine, writing, is also what I do for a living.

When I retire, I plan to continue spending most of my time writing — hopefully even a few novels. I also enjoy travel, so I plan for that to be a big part of our retirement (money permitting).

Nurture your relationship with your spouse

Frank told me it's crucial to have a solid relationship with your partner if you plan to retire early, as you'll spend a lot of time with them.

He and my mother-in-law have been married for almost 60 years and still spend almost all day every day together.

I love my husband dearly and he's my best friend, but I'm guilty of focusing a lot of my time and energy on our three young children. My husband tends to be at the bottom of the pyramid in our household.

After chatting to Frank, I know I want to make some changes with our relationship, and to make my husband more of a priority. To start, maybe we'll plan more date nights or take time to map out our retirement goals together.

At the end of the day, the kids will move out some day, and it will just be him and I, so we need to keep the magic alive.