Advanced Electrical Insulator Company is considering replacing a broken inspection machine, which has been used to test the mechanical strength of electrical insulators with a newer and more efficient one. If repaired, the old machine can be used for another five years although the firm does not expect to realize any salvage value from scrapping it in five years. Alternatively, the firm can sell the machine to another firm in the industry now for $5,000. If the machine is kept, it will require an immediate $1,200 overhaul to restore it to operable
condition. The overhaul will neither extend the service life originally estimated nor increase the value of the inspection machine. The operating costs are estimated at $2,000 during the first year and are expected to increase by $1,500 per year thereafter. Future market values are expected to decline by $1,000 per year. 

The new machine costs $10,000 and will have operating costs of $2,000 in the first year, increasing by $800 per year thereafter. The expected salvage value is $6,000 after one year and will decline 15% each following year. The company requires a rate of return of 15%. Find the economic life for each option and determine when the defender should be replaced.