What a home office, you can either depreciate it, or take the standard $5 per sq foot deduction up to a maximum of 300 sq ft. With the standard deduction for that, you're not required to recapture it. So check that, as it's most likely the former CPA opted for the $5/sq foot deduction on that home office.
Rental real estate property is a different story. You definitely want to depreciate it. That's because when you sell the property you are required to recapture the depreciation taken or the depreciation you should have taken, whichever is higher, and pay taxes on it in the tax year of the sale.
