This being the case actual rates may vary depending on worksite condition, age and availability of equipment to be used and the attachments needed. The rates listed are based on five (5) year old equipment and such rates are mere standards. Basic reference to the average utilization per year for type of equipment have been incorporated and useful features such as economic life, tire and undercarriage life and salvage factor have been sourced from a reputable cost reference and included in the formulation for a more realistic approach in the estimation of recovery instrument. Another fomulais used for light and medium equipment. As in our earlier edition we are using dollar rates for the computation and we have considered factors like equipment rating, testing and standardization cost. We have factored in such variables like acquisition cost, depreciation, spare parts replacement costs, operators wages, full dollar fluctuations and interest rates, ect. Industry experts and association members have been consulted to come up with the best possible approach for the computation of rates that would approximate the lessor's operating cost and other incidentals. The 24th edition of the ACEL Equipment Guidebook has been updated to conform to the volatility of the changing market.