Cost segregation

Engineering study that reclassifies portions of a property's basis into shorter depreciable lives.

A cost-seg study breaks the building into 5-year (carpet, appliances), 7-year (cabinetry, equipment), and 15-year (site improvements, landscaping) buckets — which can be bonus-depreciated. Studies cost $5-15k for SFRs, $15-50k for commercial. Usually pays off if you'll hold 5+ years and have passive losses to absorb.