The discovery of radio jets in numerous Galactic black hole X-ray binaries has enabled the comparative study for black holes of vastly different mass scales. The available evidence suggests that jet formation in low-efficiency accretion flows is a scale invariant process, with manifestations in the X-ray radio relation in X-ray binaries and the "fundamental plane of black hole accretion" across the entire mass spectrum. Application of the underlying scaling relations allows a calibration of the cosmic jet power and feedback efficiency. These relations raise a number of interesting questions: What is the relation between jets from black holes and those from accreting neutron stars? Can we develop a similarly successful quantitative comparison of radio lobes and cavities between X-ray binaries and AGN jets? How does black hole spin factor into these relations?