A power supply (100) comprising a power stage (110), a monitoring stage (150) and a user interface (170). The power stage (110) comprises a primary and secondary side (112, 132) with electrolytic capacitors (116, 136) provided with respective temperature sensors (118, 138); a voltage sensor (140) for the input voltage; a current sensor element (142, 144) for sensing output current. The monitoring stage (150) comprises an A/D converter (152) receiving information from the temperature, voltage and current sensors; and logic means (154-162) to perform calculations on the information received by the A/D converter. The calculations yield estimates for lifetime, aging rate and current load. An operating statistics memory (162) stores history data based on calculation results. Presentation means (164) convert the lifetime estimate, aging rate estimate and load level estimate to respective formats presentable via the user interface (170), which comprises respective indicators.