What is the accepted norm for labeling axes in plots/graphs? Is it best to use the variable, spell our the variable, or a combination of both? For example, to label a time axis, we could write: t (s) or Time (s) or Time, t (s).

What are best practices (if any exist) for labeling axes in plots/graphs for academic documents, such as theses, publications, or presentations?

Possible options are to use the variable, spell out the variable, or a combination of both. For example, to label a time axis, we could write: t (s) or Time (s) or Time, t (s).

Are there any objective reasons to prefer one style over another, assuming the publisher does not specify which to use? Or sources suggesting a particular format?

I have browsed many journal requirements, but haven't found any that specifically address this.