How is depreciation typically calculated for personal property?

Depreciation calculation aims to reflect the item's actual diminished value due to age and use. Standard approach: depreciation = (age / total useful life) × replacement cost. Example: a 5-year-old refrigerator with a 15-year useful life is depreciated 5/15 = 33% from replacement cost. A $1,500 replacement-cost refrigerator has $1,000 ACV. Considerations: (1) Useful life — varies by item type; industry depreciation guides (like Marshall & Swift, Xactimate, ACV Boss, and proprietary insurer guides) provide standardized expected lives; (2) Condition adjustments — items in better-than-average condition for their age depreciate less; items in worse condition depreciate more; (3) Pre-loss condition — assessing condition before loss can be difficult; documentation helps (receipts, photos, manuals); (4) Type of depreciation — physical (wear and tear, deterioration), functional (obsolescence, outdated technology), economic (market-related). Specialty items (artwork, collectibles, jewelry, antiques) may appreciate or have complex depreciation patterns; appraisals support the values. Roofs and structural elements use age-based depreciation tied to expected lifespan. Disputes about depreciation are common; experienced adjusters explain their methodology clearly and document support. Public adjusters often negotiate depreciation downward; private appraisers may need to resolve disputes.