My tax person once said, when I was worried about getting mine done on time, that if you ARE OWED money, they don't care if your return is late. If you owe money, it had better be in on time.
She said it, I didn't, but it makes sense. I'd never intentionally be late with mine, 'cause it isn't so big either way that I'd be confident whether I'd owe or be owed.
My husband died last July. So I got to file married filing jointly for 2024. For some years we'd get money back (Federal) due partly to his high medical/Rx expenses (something Kevin got wrong in an earlier post), deductible business expenses (no longer a deducation for several years now) and how gambling winnings/losses used to be treated.
This year I owed a little, partly due to gambling winnings, manageable but...where the heck is that money now? My CPA gave me forms to send some $ in quarterly. I don't have to as I'm not self employed, but she is the second person to warn me that with my retirement income, by filing single I'll have tax shock next April if I don't.