Checking off that 'to-do' list? Check! Keyword expansion is important to ensure you capture as much volume as you can. When you launch a campaign, it's important to put in your due diligence to identify the most appropriate keywords to include in your campaigns, which can be done through keyword research and reviewing of historical keyword performance data. However, no matter how well you build your starting keyword set during keyword generation, it's unrealistic to believe you will have captured all appropriate keywords for your campaign.
Here's what you'll want to do. Keyword expansion includes mining search term data to identify search terms that have matched to a phrase, broad or broad match modified keywords and have converted that warrant being added to a campaign. Similar to keyword negation, it should take place daily for the first two weeks of a campaign's life and then weekly on an ongoing basis.