During the 1980s, Blockbuster Entertainment became one of the largest national video rental chains in the United States. With its rapid growth came significantly increased stock prices. Then, in 1988, Blockbuster changed the amortization period for its videotapes from nine months to 36 months. Why do you think Blockbuster changed its estimate of the useful life of its videotapes? What do you think happened to Blockbuster’s market value?