Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

Why are estimated taxes due “early” for the 2nd and 3rd quarters only?
I suspect that the payments were originally due near the end of each quarter (March 15, June 15, September 15, and December 15) but then the December payment was extended to January 15 to allow for end-of-year totals to be calculated, and then the March payment was extended to April 15 to coincide with Income Tax Return filing.