Thanks for your awesome response. You are right. I should (and will) go with the safe harbor rule because my income is somewhat unpredictable and uneven. It also makes sense because my 2026 income is almost certainly going to be much larger than 2025. I will also use the safe harbor for my state taxes. It is the same as the 100% federal rule. I will need to be sure to set aside enough cash to cover the large tax payments that will be due on both the federal and state returns in April, 2027.
Regarding my concern about an error in the prior tax return impacting the subsequent return, I am not aware of any errors in my returns. However, taxes and the software are complicated and honest mistakes can happen, though they are rare.
You may not be a CPA but you undoubtedly qualify for an honorary CPA certificate.
Thanks again. Good luck to you.
