The time that something has to be done is getting closer. You may have to pay your taxes and the due date (when the taxes are to be paid) is a month away. While a month may seem like a long time, it is not as long as you think (or, as it appears to be). This is an odd thing to say. Time is a set standard for most people. I usually see this type of warning on an outside mirror or a car - objects are closer than they appear.WARNING:
"Due dates are closer than they appear!"
I don't understand it.
I assume it's a play on exactly that mirror phrase.