It will be very useful if there was a function which would insert fixed date. Functions NOW() and TODAY() are changed every time spreadsheet is updated but there are times when user want to insert fixed date. Example (in cell B1): =IF(NOT(ISBLANK(A1)); FIXEDDATE(); "") Let's say you want to add some invoice amount do a spredsheet, FIXEDDATE() function could automatically populate cell with today's date in B1 when amount is entered in A1. People have been asking for this feature: OOo: https://forum.openoffice.org/en/forum/viewtopic.php?f=9&t=82400 Google Sheets: https://productforums.google.com/forum/#!topic/docs/AD3EsxZVhG8 But only solutions are scripts and macros and very few users can effectively use them. It would be more convenient if this feature were available as a (plain) function.
Think about it. How should FIXEDDATE() in a formula expression determine whether it was ever executed. Rather use the Ctrl+; keyboard shortcut (or whatever keys your locale maps that to) to insert the current date into the current cell, if you don't want to use a macro that listens to an input cell and writes the date elsewhere.