I've got a spreadsheet with cells that I want to be user-editable, but that I also want to have "default" or "placeholder" values in, whenever there is no user-entered data. There's a couple good use cases for this:
Prevent formula errors, while providing reasonable assumptions when a user has not entered (or has deleted) their own value.
I could use conditional formatting to alert the user to default values, so as to prevent their ignorance of them - they can then make an informed choice as to whether that value is still appropriate or not for the intended calculations.
Give a short description of what is intended to be entered in the cell, without having to have a separate "instructions" segment or document. This would also eliminate the need for a nearby "Label" cell, in some cases where it's really not appropriate.
To accomplish what I want, I need some formula, script, or other advanced spreadsheet option that will do the following:
Show the default value in the cell before user enters data.
Allow the default value to be found by any formulas referencing the cell, when there is no user-entered data in that cell.
Allow the user to freely (naturally, exactly as they would do with any "normal" cell) overwrite the displayed value with their own value or formula, and have the user-entered data found by any formulas referencing the cell.
When cell is blanked by deletion of user input, revert to default value.
Is there a way to do this in Excel, or am I asking too much of a spreadsheet program here?
