The Problem with VLOOKUP
VLOOKUP always searches to the right of the lookup column and relies on a fixed column index number. As soon as a column is inserted into the source table, the index shifts and the formula silently returns the wrong value. In a billing file shared among several people, this is the leading cause of invisible errors.
Why INDEX/MATCH Holds Up Better
INDEX(result_range, MATCH(value, lookup_range, 0)) points to named ranges rather than relative positions. You can insert, move, or hide columns, and the formula continues to point to the correct data. It also allows for left-side lookups, which VLOOKUP cannot do.
What About XLOOKUP?
On Microsoft 365 and Google Sheets, XLOOKUP combines both advantages with shorter syntax and native handling of missing values. If your company is still on Excel 2019, stick with INDEX/MATCH to ensure workbook compatibility.
Best Practice
Always wrap your lookup in IFERROR() to display a readable business message (e.g., "Unknown Client") rather than a raw #N/A in a report intended for management.