A fundamental feature of cellular growth is that total protein and RNA amounts increase with cell volume to maintain approximately constant concentrations, a phenomenon known as global concentration homeostasis. Increasing evidence suggests that this scaling helps define optimal cellular physiology and has been linked to both senescence and ageing. We recently demonstrated that mRNA scaling in yeast is achieved by two processes that act in concert: elevated total transcriptional output and a global slowdown in mRNA degradation. I will first present our work supporting a dynamic equilibrium model in which global RNAPII transcription at a given cell size is set by the mass action recruitment kinetics of unengaged nucleoplasmic RNAPII to the genome (Swaffer et al., Cell 2023). I will then present unpublished data showing that competition between translational initiation factors and mRNA decay enzymes generates a cytoplasmic feedback mechanism that buffers mRNA decay rates as cells enlarge. Finally, I will discuss ongoing work examining the consequences of disrupted mRNA scaling, focusing on its impact on translational efficiency.