Excel has an option for formula calculation, automatic vs manual. The default is automatic. There is also a 'calculate now' button to use for if you have manual calculations set. I would expect that if automatic calculations set, then my code changes would trigger calculations on affected cells. I can't speak for Sheets, but most Excel users would probably expect that behavior.
Maybe? The closest analog in Excel would be to define a VBA function call it from a sheet, go back to the VBA editor, change the definition and see the function be run automatically everywhere with the new code. That does not happen, I just tried
