Stellar bars are a common structural component of disc galaxies and are thought to play an important role in their formation and evolution. However, the relative importance of intrinsic galaxy properties, environment, and assembly history in determining whether a galaxy hosts a bar remains an open question. Using two observational samples, we investigate the dependence of bar occurrence on stellar mass, morphology, and environmental properties, finding consistent and complementary results. Stellar mass and morphology are the primary factors associated with the likelihood of hosting a bar, while the apparent dependence on cluster mass and cluster-centric distance is largely explained by changes in the morphological composition of galaxies. Our analysis also suggests that interactions with nearby galaxies and processes such as ram-pressure stripping can influence the evolution of barred galaxies, with the latter associated with enhanced central star formation in some barred systems. Finally, we use the TNG50 and TNG100 cosmological simulations to investigate bar occurrence in relation to environment and assembly history. These results indicate a mild environmental dependence, while stellar mass and, in particular, galaxy assembly history provide important additional connections to bar formation and evolution. Together, these studies provide a unified view in which the incidence and evolution of stellar bars are strongly connected to galaxy morphology and intrinsic properties, while environmental interactions and assembly history can further shape their evolution.