A common understanding of inertia likens it to a snowball gaining speed and weight as it collects more and more snow on its way down a mountain. It would, in fact, be gaining inertia but not because it was rolling down a mountain but because it was gaining mass on its journey. As it gains inertia it becomes increasingly difficult to stop but, conversely, when it does stop it is equally as difficult to get moving again.
Inertia is the tendency to resist change, which applies to stopping something or someone doing what it, or they, are doing or getting them to do something they are not. And, in theory, they are both the same. We find this when attempting to stop bad habits or start good ones though they follow the snowball principle in that their inertia increases the further we let them roll.
This is an excellent principle for directing your life. For most of us there are new beginnings throughout our lives such as marriage, a new job, moving house, changing careers but the snowball principle holds throughout. Beginning from nothing can seem desirable but it's never a reality - if we are not carrying baggage from our past we're carrying genes from our ancestors. But starting from absolute zero would not be advantageous, as we would have no experience to draw on and no investment to build on.
As I write this I can think of people who have well paid jobs, a very nice house and substantial company pension, all built up over the years. They started out with a lump of snow at school or university and have steadily built their snowball. It seems like they can just cruise through the rest of their lives having built that inertia. My snowballs seem to have got no bigger than a large football before they fell apart or just melted in the sun. I've never built up enough inertia to keep me going under my own steam.
In all that I've done and experienced I've built up a wealth of knowledge and skills that, in some ways, are more substantial than bricks and mortar, bonds and company pensions. Snowballs build quickly once a substantial amount of snow has been gathered. It's not so much the size of your snowball that determines the inertia as the availability of snow. I don't have the luxury of massive inertia but with effort and determination I can rediscover my fields of snow even as we approach April.