:) If you honestly categorize repair cost based on

1) true repair cost (plumbing, electrical, painting, replace worn carpets, etc)

2) improvements (upgrading kitchen, replace new AC, replace roof, upgrade floor from carpet to hardwood)

1) can be used to write off rental income.

2) has to be depreciated over the IRS specific depreciation schedule.

But there are murky areas that IRS will never bother to look. I think they have internal filters for large amount of expenses. :)