Absolutely! In fact, using formulas is a powerful way to create customized conditional formatting rules in Excel. Here's why formulas are useful:

* Flexibility: Formulas allow you to define specific conditions based on calculations or comparisons between cells. This goes beyond the built-in formatting options like highlighting greater than/less than a certain value.
* Automation: You can leverage functions and references to automate how formatting is applied based on your data.
* Complex Rules: Formulas enable you to create intricate rules that consider multiple factors or combine conditions using logical operators (AND, OR) for a more nuanced approach.

Here are some examples of using formulas in conditional formatting:

* Highlight cells above average: Use a formula like `=A1>$B$1` (where A1 is the cell you're formatting and B1 contains the average) to highlight cells with values greater than the average in column A.
* Format based on text content: Use a formula like `=SEARCH("shipped",A1)>0` (where A1 contains text) to highlight cells where the text "shipped" appears anywhere within the content.
* Color code based on date differences: Use formulas with TODAY function to compare dates and apply color coding based on how recent or overdue something might be.

Remember, the formula you use will depend on the specific formatting condition you want to achieve. Excel provides a user-friendly interface for creating conditional formatting rules with formulas. You can simply select the cells, go to "Conditional Formatting" and choose "New Rule." Within the rule creation options, you'll find a section for "Format values where this formula is true" where you can enter your desired formula.