Meca Concrete purchased a mixer on January 1, 2014, at a cost of $45,000. Straight-line depreciation for 2014 and 2015 was based on an estimated eight-year life and $3,000 estimated residual value. In 2016, Meca revised its estimate and now believes the mixer will have a total service life of only six years, and that the residual value will be only $2,000.