The best time to perform a Cost Segregation Study is the year in which the building is purchased, constructed, or renovated. This allows an owner to immediately start realizing maximum tax savings and will accurately classify assets before the building starts depreciating. It is also when cost and construction documentation is fresh in everyone’s mind. This makes supplying your cost segregation provider with all the necessary documentation much easier and allows the study to be completed in a timelier manner. However, if it is already later than that, do not worry; the IRS allows you to "catch-up" any missed depreciation in the current year by filing a form 3115 (Change of Accounting Method) without the need to file an amended tax return. As always, your CPA should be involved in any decisions related to the timing and/or need of the cost segregation study based on the your tax situation.