just - for - you hardware consultants purchased a building for 644000 and depreciated it on a straight-line basis over a 30-year period. the estimated residual value is 104000$. After using the building for 15 years, Just - for - you realised that wear and tear on the building would wear it out before 30 years and that the estimated residual value should be 88000$ . starting with the 16th year, just - for - you began depreciating the building over a revised total life of 25 years using the new residual value. journalize depreciation expense on the building for year 15 and 16