The secret to getting strong and staying strong is... starting and not stopping!
I know this sounds simple but, in reality, it's tremendously hard. Committing yourself to a training program takes a level of commitment that most don't have. But you can tell those who do. They are a breed apart, thy carry themselves differently and they have a certain "something" about them. They are across the board happier and more mentally resilient and are able to handle the wear and tear of the years with grace.
What does it take to become one of these outliers? Find a strength and conditioning program that you enjoy and stick with it. Not for just a few months, but for years, and possibly decades. I can guarantee that it will be the best investment you ever make and that the dividends that it pays are priceless.