The decline in value of a depreciating asset starts when you first use it, or install it ready for use, for any purpose including a private purpose. This is known as a depreciating asset's start time.
Although an asset is treated as declining in value from its start time, a deduction for its decline in value is only allowable to the extent it is used for a taxable purpose (see Glossary).
If you initially use a depreciating asset for a non-taxable purpose, such as for private purposes, and in later years use it for a taxable purpose, you need to work out the asset's decline in value from its start time through the years it was used for a private purpose. You can then work out your deductions for the decline in value of the asset for the years it is used for a taxable purpose see Decline in value of depreciating asset used for non-taxable purpose.