Q3 estimated tax payments are due September 15. Most business owners already know the date. Fewer stop to think about how they're landing on the number they send in. A lot of the time, it's last quarter's payment, rounded up a little "just in case." That's not an estimate. That's a guess — and guessing wrong costs money in both directions. We see this a lot with small business owners here in Pasco and Pinellas Counties, especially contractors and service businesses whose in