Certain types of business property are called "listed property" and are subject to special depreciation restrictions.
Listed property includes:
Generally, your business usage of listed property must exceed 50 percent in order for you to take the special expensing election or to depreciate the property under MACRS. Otherwise, you must use straight-line depreciation under the ADS method, using the appropriate ADS class lives for the items.
If your business use of listed property drops below 50 percent in any year after the first year you use the property in your business, but before the property's depreciation period has expired, you may have to pay back some of the excess depreciation you claimed. Specifically, you'll have to treat the difference between the ADS depreciation and the depreciation you actually claimed (including any amount you expensed in the first year) as ordinary income in the first year you no longer use the asset more than 50 percent for business.
Recordkeeping chores. And, as you might guess, you'll have to keep records showing that your business usage was at over 50 percent of total usage of the property. This means that you should keep a log showing each time the property was used, for how long, and for what purpose.
For cars, your mileage
records will generally suffice. For computers, cameras, audio/video
equipment etc., you should keep a log noting the date, length of time, and
purpose for each use of the item. Personal or family use can simply be
designated "personal" but business use should show enough detail to
enable you to prove the relationship to your work, if necessary in an audit.