When replacing capacitors in a switching power supply, it's crucial to match the voltage rating, which should be equal to or greater than the original, while maintaining the same capacitance value in microfarads (uf). Higher voltage ratings can provide better reliability but may increase size and cost. For electrolytic capacitors, proper polarity must be observed, and equivalent series resistance (ESR) is an important factor that affects performance, especially in switching applications. A lower ESR is generally preferred to minimize ripple voltage and ensure stability. It's recommended to consult the specifications of the capacitor being replaced to ensure compatibility.