Preventive maintenance schedule

Annual work is twelve months, not 365 days. January 31 plus one month lands on the last day of February. HVAC every 3 months on the 1st stays the 1st after a late November 18. Lawn every other Saturday stays Saturday after a late Monday. Bins stay Tuesday after a late Thursday.

Oil on Truck A at 5000 miles or 200 engine hours is whichever hits first. Fill at or under 20% is due when the tank is 18%. Coolant at or over 220 is due the other way. A truck already at 87240 starts there. Last oil at 85000 with the dash at 87240 leaves 2760 miles.

A guessed manufacturer interval would look like due state. So would a fake shop visit invented only to start the odometer. Completions and the interval you stored move due. Asking for Friday's board moves the clock; it does not invent the miles you will drive by Friday.

Ask Muse to store the interval you said, then ask what is due. The Worker does the arithmetic. Free on Cloudflare Workers and D1.