Synthesis dependence is one of the biggest challenges faced by the field of quantum materials. Current synthesis methods introduce sample-to-sample variations that are poorly understood and difficult to control. This, in turn, leads to unreliable and unreproducible quantum materials and a lack of consensus across the community on their properties of interest. Here we highlight several examples of this synthesis dependence and propose steps that could overcome its challenges to deliver more reliable, reproducible and ultimately useful quantum materials. Interesting results in quantum materials often suffer from substantial inconsistencies between samples. This Perspective advocates for more careful study of synthesis dependence to realize the full potential of quantum materials science.