Here are a few ways that you could use a vlookup to make your life easier:
1. A list of codes which exist in a bigger database from which you’d like to return specific details.
eg. A front page which you’d like to list product codes in and you want to automatically fetch the descriptions and prices from a larger database.
2. A front page containing values which you’d like to use a reference sheet to assign a rating based on some thresholds.
eg. A list of students’ results to which you’d like to assign a grade (such as a B grade for between 65% and 74%)
3. A form in which you’d like to enter a value and a result to automatically appear next to it.
eg. A user form with a dropdown box which you can select a suburb from that automatically returns the postcode.
4. Using a string (word, number, code) to determine some sort of classification
eg. You could use a a postcode to determine the state / province (the lookup database would only need the vlookup ranges in it instead of every postcode).