Advice required for this function

Try

=IF(COUNT(B5:F5)<5;"Incomplete";IF(COUNTIF(B5:F5;">="&TODAY())=5;"GO";"NO GO"))

The first part of the code =IF(COUNT(B5:F5)<5;"Incomplete" works. However, for the second portion, there seems to be some logic error. Even though the dates I've entered for cell B5 to F5 is lesser than TODAY(), it still displays "No Go"

Dates in cell as shown:
12/09/08
16/09/08
14/03/06
08/08/08
16/09/08

Your description doesn't match your formula in the first post. You say that "If result is TRUE it'll display NO GO" but the formula you posted returns "NO" if the test is true, i.e. all dates are greater than today.

I used the logic present in your formula, if you want the reverse just switch "NO" and "NO GO"

That's right. Apologies for the confusion.

However, I do realise that if I use the today() function to match against other cell values, it doesn't update immediately unless i changed a cell value somewhere or close and reopen the document.

Is that normal and any resolution on this issue?

Alright, did some research and today() function will only update if something is changed manually in the cells or document saved and re-opened.

Thanks for the help!