Months are pretty well and exhaustively defined. There are 13 of them. It's just that it's not enough to say that there is a 3-month interval. You need to specify either the dates or the months.
To say months shouldn't be used is sort of like saying that complex numbers or vectors shouldn't be used. They are absolutely useful. We just deal with their component parts separately.
To say months shouldn't be used is sort of like saying that complex numbers or vectors shouldn't be used. They are absolutely useful. We just deal with their component parts separately.