Closing the books feels...

Both, I understand that it is important to close the books and the end of the year. I understand that once the books are closed you are not allowed to make any adjustments  to the books.

I guess I don't understand the importance of closing the books each month. As we all know you can receive invoices for purchases that you didn't know were made and it came in two months after. I myself like to see the actual cost per month with the work that was performed. If you close month by month then it is not really accurate to me.