Real data is rarely clean: it arrives with duplicate rows, inconsistent spacing, and inconsistent formatting. Sorting (A-Z, Z-A, or a custom order) and filtering (showing only rows that meet a condition, such as a specific region or date range) are among the most-used tools for exploring a dataset, and both Excel and Sheets let you apply them without permanently changing the underlying data. The 'Remove Duplicates' tool eliminates exact repeat rows, while the TRIM function strips extra spaces that often cause lookups to fail silently -- two cells that look identical but have a trailing space will not match in a formula. Data validation lets you restrict what can be typed into a cell, for example only allowing a dropdown of valid category names, which prevents many cleaning problems before they start.