Accretion powers the most luminous phenomena in the Universe and operates essentially unchanged across ten orders of magnitude in mass, from star formation to the fueling of supermassive black holes. My research asks how far simple analytic models built from first principles can take us in understanding these flows and, where gravity turns strong, how to bring relativistic dynamics into trusted and widely used Newtonian codes. In this talk I will follow these questions up the mass scale: how solutions derived for black holes became the standard framework for interpreting protostellar accretion streamers observed with ALMA and NOEMA; how a geometric correction to Bondi-Hoyle-Lyttleton accretion resolved its long-standing failure for slow stellar winds in binaries; and how approximations that capture key relativistic effects, now part of the Phantom code, enable accurate simulations of tidal disruption events and, more broadly, of stellar and fluid dynamics near supermassive black holes. I will close with a roadmap tying these threads into a single research program for the coming years.