Homewood constructions wants to invest in a pile driving machine which initially costs $280,000 for purchase. In the first, second and third years, maintenance cost is $6000, $9000, and $12000 respectively. Salvage value at the end of the third year is $150,000. If the company decides to keep the machine beyond the third year, maintenance cost for fourth, fifth and sixth years are $9000, $11,500 and $13,000, respectively. There is a $70,000 overhead cost at the end of the third year if the machine is to be kept. Salvage value at the end of the sixth year is $100,000. If the machine is to be kept for two more years, another overhead at the end of the sixth year will cost $140,000. Maintenance cost will be $99,000 for the seventh and eighth years, and there is no salvage at the end of the eight year. If the time value of money is set based at 10%, what would be the best thing for Homewood to do keep the machine for 3 years, 6 years, or 8 years?