6. Property, plant and equipment

Property, plant and equipment comprises owned and right-of-use assets. The Company leases many assets including property, motor vehicles and office equipment.

The cost and accumulated depreciation of owned assets are as follows (in thousands):

Schedule of property, plant and equipment

Total depreciation expense related to owned assets during the years ended March 31, 2023 and 2024 was $9.7 million and $14.2 million, respectively. Depreciation expense related to in-vehicle devices is included in subscription cost of revenue.

During fiscal year 2023, the Africa segment reassessed the useful lives of its installed in-vehicle devices where, on average, the useful lives were increased from 3 years to 5 years. The reassessment of the useful lives resulted in a $1.4 million reduction in the depreciation expense relative to what would have been recognized in fiscal year 2023 had the change not occurred.

During fiscal year 2024, the Africa segment reassessed the useful lives of its installed in-vehicle devices where, on average, the useful lives were increased from 29 to 34 months. The reassessment of the useful lives resulted in a $1.2 million reduction in the depreciation expense relative to what would have been recognized in fiscal year 2024 had the change not occurred.

The cost and accumulated depreciation of right-of-use assets are as follows (in thousands):

Schedule of right of use asset