Build Against Buy, and the Real Math

1. The Comparison Everybody Makes Is the Wrong One

The build-versus-buy conversation almost always starts the same way. Somebody names the vendor's annual price, somebody else says they could write that in a month, and the discussion proceeds from there.

Both numbers in that exchange are wrong, and they are wrong in opposite directions.

• The vendor price is not what buying costs. Integration, the limits you discover afterward, and the work to leave are all real and none of them are on the invoice.
• **The one-month estimate is not what building costs