Thurber Co. purchased equipment for $695,800 which was estimated to have a useful life of 10 years with a salvage value of $12,200 at the end of that time. Depreciation has been entered for 7 years on a straight-line basis. In 2013, it is determined that the total estimated life should be 15 years with a salvage value of $5,600 at the end of that time.