Are you renting the property and receiving income? If so, you need to prorate expenses between your home and the rental property.

If it is empty and not available for rent, there is no deduction for any expense.

If the second scenario is the case and both buildings are under the same mortgage, enter it only under your primary residence in Deductions and Credits.

It is a backyard rental ADU that I received rental income on that's part of my main house that I live in.  There's a category under Wages and Income for rentals and royalties under subcateogy EXPENSES / ASSETS (DEPRECIATION) where you can input your overall real estate taxes and mortgage interest.  You can also input these values in the Deductions and Credits category.  Inputting the values in both increases my refund substantially.  My question is if I can/should do so or just input it in the Deductions and Credits category like I would normally.  If I prorate it, how much of my real estate taxes and mortgage interest can you put under Wages and Income?