No. This is not premature optimization. I have all the money to pay the taxes, it's just that I can actually come out ahead by paying with a credit card, paying

No. This is not premature optimization. I have all the money to pay the taxes, it's just that I can actually come out ahead by paying with a credit card, paying it off right away, and then taking the points and sign up bonuses on multiple credit cards. If you owe $20K in taxes, you can totally sign up for 3 or 4 cards and reap all the bonuses in one fell swoop. 2 payments per processor, PayUsaTax is 1.85%, Pay1040 is 1.87%, as long as your sign-up bonuses can beat those numbers (they easily do on many cards, see my other comment below), you can get 4 sign-up bonuses easily. I already am doing everything I can possibly do within legal bounds to reduce my tax bill. 401K, IRA, credits, you name it, I have it. The credit card thing is just at least getting my cherry back after the government took my cake.