Thanks to their amenability to both genetic and biochemical analysis, vacuoles of S. cerevisiae are valuable models for trafficking processes to mammalian lysosomes. They also have additional functions to lysosomes, and all of these processes can influence the size and number of vacuoles. Several recent papers have indicated that some vacuolar proteins participate in more than one process, and hence could be regulatory points to balance the processes and control vacuole dimensions. Studies of vacuoles from other yeasts and fungi are uncovering further roles for vacuoles, increasing the apparent requirement for such regulation. Having served as models in the past, yeast vacuoles are now well suited to develop the next generation of quantitative methods to understand organelle functions and dynamics.