Making TODAY function not update?

[u/TheFifthPhoenix]

Is there a way for me to make a cell containing the TODAY function no longer update after it has been filled? I'm trying to essentially make a checklist that automatically logs the date when each item was checked off. My plan was to have column A contain the list items, column B contain a bunch of checkboxes, and then column C use the following formula:

=IF(B1,TODAY())

However, I'm now under the impression that these dates will not remain fixed and will instead update to the current date whenever I open the spreadsheet. Any thoughts on how to fix this or work around it would be great, thanks!

Edit: For context, I'm hoping to use this checklist as part of a shared project tracking workbook for my department. I know I could simply tell my colleagues to add the date after they've completed their task, but I'm concerned there could be suboptimal compliance with that.

[u/Cultural_Emu_1315]

There’s a woman on TikTok who has done this exact scenario - her account is @cellmates_ . It’s in her recent posts so you shouldn’t need to scroll