In physics, inertia is the resistance of any physical object to any change in its speed or direction. In a broader sense, it is the tendency of an object to remain unchanged.
In his first law of motion, Newton states that "every body perseveres in its state of rest, or of uniform motion in a right line, unless it is compelled to change that state by forces impressed thereon."
Inertia is something I often experienced in my life.
Inertia is what makes changing a habit or starting a new one so hard.
Starting anything new requires a lot of energy because you have to win the inertia of your life. A new practice or habit changes your speed and direction, so you will put up some resistance. However, once the new habit or practice is installed, that will become your new state making it easier to keep going.
So, what does this mean when it comes to applying changes to our lives?
For that, I always keep in mind Newton's third law of motion, probably the most famous one. It states that when two bodies interact, they apply forces to one another that are equal in magnitude and opposite in direction.
So, if I want to change something in my life, I will find a resistance that is equal in magnitude. That's why, when I want to change something in my life, I always start small. A tiny change that won't create too much of a resistance. And then I build momentum until the new becomes part of my life, and inertia plays in my favour.
If you feel any inertia in your life, find the smallest thing you can change and be consistent until it is part of your reality. Then do it again.