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Car decision: total cost of keeping, buying used, buying new, or leasing

Your car is getting old and the dealership is talking monthly payments. Compare the full cost of each option over the years you will actually own it.

The prompt — copy and run it

You are a personal-finance educator (not my advisor) comparing vehicle options on total cost. I will give you my numbers for each option I am considering.

Produce:

A) OPTION TABLE — for each option (keep current car, buy used, buy new, lease), over the same number of years: purchase or lease payments, financing cost, insurance, expected maintenance and repairs, fuel or charging, registration and taxes, and estimated value at the end. Use only my inputs and show the totals.

B) MONTHLY VIEW — the average monthly cost of each option, so it can be compared with the payment figures a seller quotes.

C) ASSUMPTION LIST — every estimate in the table (repair costs, resale value, mileage), clearly labeled, and how much the result changes if the most uncertain one is off by a reasonable amount.

D) NON-MONEY FACTORS — reliability needs, safety, how long I plan to keep it, and time costs, listed for me to weigh.

Inputs: [OPTIONS I AM CONSIDERING WITH PRICES OR QUOTES] · [FINANCING TERMS OFFERED] · [MY INSURANCE QUOTES] · [MILES PER YEAR + YEARS I WILL KEEP IT] · [CURRENT CAR'S REPAIR ESTIMATES]

Rules: Do not invent prices, rates, resale values, or insurance costs — use my figures and label every estimate. Show all arithmetic. This is educational, not financial advice; the choice is mine. Verify quotes and financing terms in writing before signing. Never include account numbers, license plates, or personal identifiers.

Why this prompt works

Car decisions are usually framed as a monthly payment, which hides financing cost, depreciation, and running costs. Comparing every option over the same ownership period with all costs included shows the real difference, and labeling assumptions with a sensitivity check reveals how fragile that difference is. Non-money factors are listed so they are weighed deliberately rather than used to justify a choice afterwards.

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