"Most people on HN who are optimizing interest/etc to the penny" It could be I've gone wrong in my reasoning somewhere, but I decided a while ago that the inte

"Most people on HN who are optimizing interest/etc to the penny" It could be I've gone wrong in my reasoning somewhere, but I decided a while ago that the interest on savings or checking is completely insignificant compared to credit card cash back. If you have 0.01% or 1% on your checking/savings, that means you earn that much on your average balance. If you have 1% cash back on a credit card, you are earning that on the total of your charges. So over a year, it's an order of magnitude more. As far as I can see, it doesn't make any sense to go to any effort at all to get interest on the cash that you are about to spend.