Methodology
Our standard is simple: make the assumptions visible, make the math checkable, and show what would change the answer.
1. Compare the same time period
Options should be measured over the same horizon whenever possible.
2. Count costs that actually change
We try to avoid double-counting sunk costs or ignoring opportunity costs that materially change the comparison.
3. Avoid fake precision
Future resale values, repairs, prices, and behavior are uncertain. Close results should be treated as close results—not as a decisive winner.
4. Separate money from values
Safety, reliability, convenience, time, and personal priorities can reasonably outweigh the lowest estimated dollar cost. When a factor cannot be measured responsibly, we say so rather than inventing a number.
5. Show sources and limitations
Current factual claims should be sourced. Calculators should explain what they include, what they omit, and where assumptions matter most.