When you create a checkbox you need to link it to a cell on a sheet to be able to use its result. The user could overwrite that linked cell with a value or text and affect formulas that are using the checkbox linked cell. You can add a validation to make sure the linked cell only contains TRUE or FALSE.
Over the years I have had many requests to help people insert blank rows between entries is a list. Apparently it is for an input routine that requires blanks. My normal solution is a macro because it automates the process, but there is a manual technique that is quick and easy.
The TRANSPOSE function is one of only a few functions that must be entered as an the array using keyboard entry Ctrl + Shift + Enter (CSE). It allows you to switch a range from going across the sheet, to go down the sheet and vice versa.
I have mentioned before that blank cells in your data can affect Pivot Table defaults in Excel. They can also reduce the effectiveness of some keyboard and mouse shortcuts. The macro below populates blank cells in the selected range with zeros.
When you drag a value column to the value section of a pivot table, sometimes the default calculation is COUNT, not SUM. This is frustrating, but easily fixed.
When developing formulas in Excel you often need to know when a cell is blank. There are different ways to check if a cell is blank, the one you chose will depend on what you are trying to achieve.