The IUPAC system is updated periodically, and two valid IUPAC names sometimes exist for the same compound (particularly for alcohols, where both propan-1-ol and 1-propanol appear in the literature). Either form is generally accepted in coursework unless an instructor specifies otherwise.

Common names remain in widespread use in industry, biochemistry, and pharmacology. Developing fluency with both systems is a practical skill that continues to matter well beyond the introductory course.