While investigating the performances of a workbook I added a Debug.Print N
inside a function so I can see when the function code runs. N is a static
long that is increased every time. It prints also a text that allows me to
see what cell is calling the function (useful when the same function is used
in many cells.)

I use the function 5 times in 2 sheets, for a total of 10 times.

First weird thing: when I open the workbook the Immediate window shows more
than executions. The function is executed once for some cells, but 2 or 3
times for others.
I tried to close Excel and open the workbook twice: once I had 22
executions, then 20. I was expecting 10.

Second weird thing: the functions are calculated when I change a cell
referred in one function (good,) when I change a cell not referred in any
function (bad,) and when I create a new workbook and change a cell in the new
workbook (worse.)
For example: I press Ctrl+N to create a new workbook (nothing appears in the
immediate window) and press the Delete button, the Immediate window shows 14
calculations.

Thanks,
Stefano