One of the physics-related definitions of inertia is “the tendency of a body at rest to remain at rest”. But inertia applies to money too, and your life.
Think about it. How many extra bank fees have you paid because it was “too much trouble” to change banks or set up direct deposit? (I’m speaking from experience there.) How many gym memberships have you paid for and not used, because you didn’t feel like working out OR admitting to yourself that you weren’t going to use the membership? What about subscriptions that you no longer use? Have you called up and canceled them? There are many little financial things like these that cost us money just because we don’t feel like doing them.
This applies to larger aspects of our lives too, like looking for a new job. Maybe we’re unhappy at our current job, but since it pays the bills we don’t put in the effort necessary to find a new one. Instead, we stay in situations that are less than ideal. Switching jobs is one of the easiest ways to dramatically increase income, since it’s easier to convince a new employer to hire you at a significantly higher rate than it is to convince your existing employer that they should be paying you 30% more.
Don’t let inertia cost you money and opportunities.