Machine the Mechanical

Give exact, repetitive, rule-bound work to a tool, but keep interpretation and novel cases with a human.

You are comparing two mortgage refinance offers at the kitchen table, scribbling interest scenarios on an envelope. Each recalculation takes 10 minutes, you keep making arithmetic slips, and by the third pass you are tempted to just pick whichever lender seemed nicer on the phone. The math is exact and rule-bound, which is precisely why doing it by hand is wasting you.

This heuristic says give exact, repetitive, rule-bound work to a tool while keeping interpretation with a human. The cue is work that is combinatorial or easily checked: calculation, sorting, reconciliation, formatting. Run it by writing down the inputs, the rules, and the expected outputs, then building the thing once, here a spreadsheet comparing amortization, total interest, fees, and early-payment scenarios. Keep anything consequential or novel, like deciding how much risk your family can tolerate, visibly in your own hands. You will know it worked when the numbers stop being the bottleneck and your energy shifts to the actual judgment call. Do not accept the tool's output until you have spot-checked it against cases you already solved manually; if it cannot beat your manual baseline, keep doing it by hand.