Abstract.  Plasma focus fusion yields on a wide range of plasma focus devices have been reported to scale with peak tube current I_p, as I_p^3.5. This is consistent with a plasma with the same parameters (density, and temperature) scaling with size of plasma which in theory should give a scaling law of I_p⁴. Scaling laws with I_pⁿ, where n is greater than 4, is possible if the temperature can be increased with increasing current. The saturation of neutron yields for large or mega-joule devices is explained in terms of the drive parameter and energy considerations. The saturation effect is estimated to be significant for mega-ampere devices with mega-joule energies. For small plasma foci, applications drive the need for high neutron yield rate instead yield per shot. We discuss the limitations of small high repetition rate plasma focus devices and propose new experiments to confirm and break the neutron yield limits of both high and low energy plasma focus devices.