One of the common themes in contemporary global health is finding an optimal balance between investments in existing and emerging approaches to fight global health priorities. Existing interventions have been proven to be effective, but they usually have limitations. Emerging interventions could potentially bring greater gains at a lower cost, but health gains are usually uncertain and take much more time to achieve. There are no simple solutions on how to balance funding support to these two competing approaches, but some components of successful strategies are becoming increasingly apparent. Transparency over the expected return on investment, style of investment and time horizon can assist rational investment decisions.