Pub 946 (2019) Chapter 4: Figuring Depreciation Under MACRS.
the property’s recovery class, placed in service date, and basis, as well as the applicable recovery period, convention, and depreciation method
when and how to recapture MACRS depreciation
MACRS consists of two depreciation systems, the General Depreciation System (GDS) and the Alternative Depreciation System (ADS). Generally, these systems provide different methods and recovery periods to use in figuring depreciation deductions.
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Your use of either the General Depreciation System (GDS) or the Alternative Depreciation System (ADS) to depreciate property under MACRS determines what depreciation method and recovery period you use. You must generally use GDS unless you are specifically required by law to use ADS or you elect to use ADS.