Do physicists subscribe to Occam's razor? If so, how do you define 'all things being equal'? The question here is the title:

Do physicists subscribe to Occam's razor? If so, how do you define 'all things being equal'?

 A: Occam's raizor:

The principle can be interpreted as
Among competing hypotheses, the one with the fewest assumptions should be selected.

In this format it is continually used in the formation of physics theories. The simplest and more parsimonious the better. This resume about covers it:

In science, Occam's razor is used as a heuristic technique (discovery tool) to guide scientists in the development of theoretical models, rather than as an arbiter between published models. In the scientific method, Occam's razor is not considered an irrefutable principle of logic or a scientific result; the preference for simplicity in the scientific method is based on the falsifiability criterion. For each accepted explanation of a phenomenon, there may be an extremely large, perhaps even incomprehensible, number of possible and more complex alternatives, because one can always burden failing explanations with ad hoc hypothesis to prevent them from being falsified; therefore, simpler theories are preferable to more complex ones because they are more testable.

As  for "all things being equal", it is not in the wiki definition. In physics it would mean, when  all  data are modeled/predicted by the theoretical modeling in all proposed theories, choose the simplest theory with the fewer hypotheses.
