If I buy a rental property midway through the year, would I need to prorate the depreciation for the year based on the amount of time I own the property? For example, if I buy a property in September, would I only be able to use 4 months worth of depreciation?
would I need to prorate the depreciation for the year based on the amount of time I own the property?
yes.
the proration is discussed in the instructions for form 4562.
I agree with Marc.
With real estate, you depreciate on a monthly basis and you get a half month for the month you place into service.