This Maxim in a very literal way instructs us to hold on to caution so that we can be aware of what is going on around us and what is going on in our lives. It does not tell us what to be on your guard against, but rather is a general admonition to be watchful. This is a useful trait to adopt in our daily lives as it allows us to then make wise decisions with the information that we gain.
This is also a trait that allows us to avoid problems both with people and situations by being able to see them coming. When we are aware of what is going on we can go through our lives with greater efficiency and ease. It also allows us to know when to speak and when to keep silence so that we can then listen to what others are saying and possibly gain advantage in our lives.
There is a song that tells us to “Know when to walk away and know when to run”. If we are not on our guard we cannot know these things and oftentimes will stay in situations when we should be doing ourselves a favor by leaving. Being on our guard allows us to hold on to ourselves, the first step in holding onto wisdom.