Level: Basic
Inconsistent capitalization across a keyword list can cause exact-match formulas and deduplication to miss entries that are functionally identical.
The Excel Technique
The LOWER() function converts text to all lowercase: =LOWER(A2), applied down the column and pasted back as values to replace the original mixed-case text. UPPER() and PROPER() work the same way for other case needs.
Example Scenario
You've merged keyword lists from three different tools, and one of them exported everything in Title Case while the others used lowercase. A straightforward Remove Duplicates pass misses dozens of matches because "Running Shoes" and "running shoes" are technically different strings to Excel.
Where This Fits in Your Keyword Research Process
Standardizing case before deduplication or matching is a small step that prevents a surprisingly common source of missed duplicates in combined keyword lists.
Next step: Use Convert Text to Lowercase from SeoWolf's Notepad to standardize the case across all three merged tool exports before combining them in Excel, so your subsequent Remove Duplicates pass actually catches every true duplicate instead of missing case-mismatched entries.