To understand the need for PCR replicates (duplicates or triplicates) in the experimental set-up of a real-time qPCR reaction, it is good to first think about the different sources of variation contributing to the measurement values. Far too often, the experimenter is too focused on the very last step of the workflow, i.e. the final pipetting step to obtain reproducible quantification cycle (Cq) values. Sources of variation in upstream processing steps are often underestimated, and are not always adequately assessed. A good understanding of a robust workflow is key to trust the actual Cq values obtained.