I believe there would be minimal practical impact in any case. In the case of anisotropy of the physical constants, it would have to be so small that to date i

I believe there would be minimal practical impact in any case. In the case of anisotropy of the physical constants, it would have to be so small that to date independent labs around the world haven’t detected a difference outside of the measurement uncertainty. In terms Of time variance a similar logic can apply. I would also add that variation of the physical constants over the span of a few decades is not very likely in the grand scheme of the universe. It’s the same reason that nothing in your life materially changed when we switched the definition of the kilogram last year, unless you are a metrologist ;). The variations being discussed here have to fundamentally be below our current measurement uncertainties and our current measurement uncertainties are very very small.