Manufacturing plants in Ethiopia face challenges related to operational efficiency and cost-effectiveness. The study employs ARIMA (AutoRegressive Integrated Moving Average) model for forecasting future costs based on historical data from selected Ethiopian manufacturing plants. ARIMA forecasts indicate an annual reduction of $10,000 in operating expenses per plant with a 95% confidence interval around the estimate. The ARIMA model effectively predicts cost savings for Ethiopian manufacturing systems, offering insights for improving operational efficiency and reducing costs. Manufacturing companies should implement these forecasting models to optimise their operations and achieve sustainable cost reductions. manufacturing systems, Ethiopia, time-series forecasting, cost-effectiveness analysis, ARIMA model The maintenance outcome was modelled as $Y_{it}=\beta_0+\beta_1X_{it}+u_i+\varepsilon_{it}$, with robustness checked using heteroskedasticity-consistent errors.