Composite life equals the total depreciable cost divided by the total depreciation per year. Section 280F was enacted to limit certain deductions on depreciable assets. This convention applies to all depreciable tangible personal property. Under current law, small businesses may expense up to $100,000 of investments in depreciable assets. A person with depreciable property must know when to start depreciating his/her property. The asset is referred to as a depreciable asset. Many tax systems prescribe longer depreciable lives for buildings and land improvements.