Based on the information you've provided, you can claim depreciation on the rental periods of your apartment in Boston. You first rented the property short term from 2015 to 2018, and then rented it again from 2021 to its sale in February 2023. To calculate the depreciation, you need to consider the periods when the property was used as a rental. You can use the Modified Accelerated Cost Recovery System (MACRS) to determine the depreciation. Residential rental property is typically depreciated over 27.5 years using the straight-line method. Here's a step-by-step process: 1. Determine the cost basis for the apartment, which typically includes the purchase price and any associated costs (excluding the value of the land). 2. Allocate the cost basis between the building and land. You can use the property tax assessment or an appraisal to determine the land-to-building value ratio. Depreciation can only be claimed on the building portion. 3. Divide the building portion of the cost basis by 27.5 years to calculate the annual depreciation amount. 4. Multiply the annual depreciation amount by the total number of years the property was rented (excluding the time it was your primary residence). 5. You also need to calculate the depreciation for the period between January 1, 2023, and the date of sale in February 2023, which is a partial year. Usually, the IRS allows using a mid-month convention, meaning you can claim half of the monthly depreciation for the month you sold the property. You'll need to report the depreciation on Schedule E of your tax return for each year the property was rented. Also, when you sell the property, you'll need to report the depreciation for recapture. The accumulated depreciation allowed or allowable will generally be subject to a 25% tax rate as unrecaptured Section 1250 gain. Please note that this information is a general guideline, as your specific tax situation may be different. It is best to consult a tax professional to ensure accuracy in calculating and claiming depreciation.