Hubble constants (HCs) have been estimated based on the CMB, on Cepheid variables, gravitationally lensed quasars, Type 1 supernovae, and red giant luminosity. Not all agree within their estimated error bounds. This has been represented by some as a conundrum. Is it? The mean age of the universe when each type of source emitted its electromagnetic radiation differs among the source types. E.g., the CMB was emitted within a few hundred thousand years of the Big Bang, according to the prevailing theory, and the value estimated by the ESA Planck Mission based on its analysis of the CMB, 67.8 km/sec/MPc, is the lowest of current estimates. If the HC varies with time, could not the various HC estimates be reconciled based on the average age of the universe for each emission source type?