The part about writing the same fill up "from two angles" is what gets me. Do you log the receipt right when you get home, or does stuff sit in your wallet for a week and then you end up entering it twice because you forgot the first time? I ask because my pile of receipts is exactly where my doubles come from, not the notebook itself. And when you moved that $40 to the car repair jar, did you write a little note next to it so future you knows why it's there? I've had jars that slowly turned into mystery money because I never wrote anything down.

That "limestone cave" line made me laugh because I know exactly what you mean. My faucets out here in the northeast heights get that same white crust and I used to think it was just soap scum. Hard water is a real pain and no little screw on filter is going to fix 17 grains. You basically proved the guy's quote was fair. I bet your water heater lasts longer now too, since it isn't fighting all that mineral build up.