Recent advances in fluorespirometry have allowed to measure multiple parameters of mitochondrial function; yet protocols vary widely between research groups, organisms, and tissues, sometimes without adequate justification or with assumptions that are not supported by data. This is particularly clear in Drosophila studies, a common model organism in biological research, with increasingly popularity in mitochondrial research. We first surveyed the literature on Drosophila fluorespirometry to compare and contrast approaches used in the field. Then, we showed that contrary to previous assumptions based on mammalian studies, oxygen diffusion is not limited in the permeabilised thoracic muscle of this species. We further compared the permeabilization and homogenising approaches, showing the former to be more adequate in Drosophila. Finally, we assessed the concentration-dependent effect of various commonly used fluorescent probes on mitochondrial respiration, showing that some probes strongly affect mitochondria and that careful choice of concentration and probe needs to be taken. The objective of this study is to give recommendations and work towards a harmonisation of the protocols for assessing mitochondrial function in fruit flies. This upload contains the raw data supporting these findings.