A taxpayer with some rental properties comes into a nontaxable major windfall and decides to do some long-needed work on these properties. He spends $100,000 on significant renovations to each property, completely overhauling all of them at the same time for a signficant increase in their value and usability. He tries to take this $100,000 against the rental income as an expense and his return is later selected for audit. Why?