In this case, goodwill should be tested for impairment at the end of 2024.
How to solve
Compute the book value of the plant and equipment and patent at the end of 2024.
Plant and equipment:
Original cost: $150 million
Accumulated depreciation: $30 million ($150 million / 10 years * 3 years)
Book value: $120 million
Patent:
Original cost: $90 million
Accumulated amortization: $36 million ($90 million / 5 years * 4 years)
Book value: $54 million
When should the plant and equipment and the patent be tested for impairment?
Plant and equipment:
The plant and equipment need an impairment test whenever signs show possible impairment, like decreased fair value, reduced profitability, or an early sale or disposal expectation before their useful life ends.
Patent:
The patent needs an impairment test if there are signs of possible impairment, such as decreased value, reduced profitability, or an expectation of abandoning it before its useful life ends.
When should goodwill be tested for impairment?
Goodwill requires an annual impairment test. Additionally, if there are signs of possible impairment—like reduced business unit value, profitability, or a plan to sell—the goodwill should be tested.
In this case, goodwill should be tested for impairment at the end of 2024.