Estimated basic pay data may be used for the month of September if actual figures are not available timely.

WHITEHOUSE: M-03-01, Business Rules for Intragovernmental Transactions, Attachment B | The White House

You may feel most of it is junk mail, but you could also be missing out on important notices or deadlines if you do not open your mail in a timely manner.

FORBES: Can Financial Procrastination Cause Heartburn?

How much more information do I need so that I can make the decision in a timely way, even if I am not totally comfortable yet?

FORBES: Magazine Article

If you timely file for your extension, you will not be subject to the late-filing penalty, which is normally 5% of your unpaid balance per month.

FORBES: Not Ready To File Your Taxes? Extension Form, Details Available