We are each given a measured amount of time to live our lives, and we don't know how much of it we have in our allotment. It is a finite resource, yet we have no choice but to spend it at a constant rate throughout our lives, so it is important to ensure that we don't waste it. Spending too much of our time on the wrong things can leave us without time left to do things that should or must be done. No-one wants to come to the end of their lives full of regrets about how their time was spent.
The 24-inch Gauge is symbolic of our need to manage our time to ensure that we use it wisely and spend it well. Most of us would rather sit and watch a sporting event than go to church, or help someone in need- it's human nature to seek out those things which give the most reward for the least effort, and things which are rewarding in some way for no effort at all can easily become far too large a part of how our time passes. The measure and allotment of our time in proper proportion to those pursuits which are essential to the improvement of our minds and souls, and those of the others around us, helps us to ensure that we are not wasteful of the time we have been given, and do not get distracted from dedicating time to making ourselves and our world better.
Tools do not do their own work, and many tasks are impossible to accomplish for a man without tools. We all have bad habits, vices, pursuits and preferences that we wish we could change, but forcing ourselves to change those things can be like trying to shape a rock with your fingers. I am not a strongly self-motivated person, and find bad habits very difficult to change in myself.
The Common Gavel represents how becoming a mason provides us with a tool to help mold ourselves into the sort of person we want to become. Having the right tool for the job can change that job from impossible, to simple -- or at least into something to which a successful completion can be envisioned.
Masonry provides a way to help us invest some of our time in worthy and honorable pursuits, helping others and honoring God - but in recognition that we are men, not saints, allows that our baser needs must also be met - keeping bread on the table, and enjoying ourselves in tasks which serve no other purpose but enjoyment, are also essential for our lives to be full and happy ones. It provides the tools we need to shape ourselves into better men, and improve the world around us.