Are universal-fit car seat covers actually one-size-fits-all?

Not literally. Universal-fit covers are cut to stretch over the most common bucket-seat and bench shapes, but verified-purchase reviewers across these listings repeatedly note that fit quality varies by vehicle, that side airbags and integrated seat controls can complicate installation, and that bolstered sport seats are the hardest to cover cleanly. If you want a tailored look with no bunching, a vehicle-specific custom-cut set is the safer bet.