I've seen a chart where software development complexity grows 3 times on each of these steps. For example:

• implement a business logic: 1 day
• cover with tests: 1 * 3 = 3 days
• write documentation: 1 * 3 * 3 = 9 days
• make it installable by other users: 1 * 3 * 3 * 3 = 27 days