Accretion disks play a critical role in planet formation, and in compact object and black hole astrophysics. I will discuss the implications of recent numerical simulations of astrophysical disks for both classes of system, which challenge long-held assumptions as to how disks work. In protoplanetary disks, the non-ideal physics of the Hall effect appears to dominate disk evolution on planet-forming scales, and this may lead to a bimodal distribution of planetary system properties. In black hole disks I will argue that strongly magnetized disks provide an appealing framework for addressing a range of unexplained observations. I will discuss the obstacles and prospects for developing a theory for the long-term evolution of both planet forming and black hole accretion flows.
