I skip the first quarter completely. Pay the second, third and fourth within a week of being due.
Pay the final amount due during the week of the 4/15. (Thats why I skip the 1st quarterly)
BOE just got 3 years back pay after recalculating "out of district" purchases and making adjustments. Wasn't a lot of $, but took up time. (Like $400.00 total)
(They also hit my wife up for 20 cents over her little jewelry making hobby because of a booth she had at a town fair, no BS. Damned postage for all the letters was several dollars, real money maker THAT was!)
I am mailing Fed, and 2 States off today as it is the only day I will be in town to do so before the 18th.
Todays payments are over 30K alone. Which is probably small time compared to yourself and many others here.
The reasons people file at or near the due date are varied.
Statistically, small businesses and LLC's draw more audits when filing early, according to the data I have been shown. I don't know how true it is, if at all, but I respect the data.
I carry audit insurance with my CPA, and have nothing to hide, but the hassle of being audited is something I don't care to go through if I can lower my chances.
Having been through a field audit (and coming away clean) the first year I was a 1099 employee, I have not been dinged since I incorporated and started filing at or near the deadline.
It is easy to throw out idealistic reasons for filing early or not, but when it comes time to sign away that check for 20-30K every 3 months, I would bet that most would change their tune and hold onto it until they HAVE to sign it.
For the record, my bills are a different story. I pay ALL our bills as early as I can, and pay off all charges monthly, RARELY carrying CC debt for more than 60 days.