[Phil G4SPZ]

Measuring capacitance often doesn’t tell you much about the condition of an electrolytic capacitor, the other key values being leakage resistance (effectively a resistor in parallel with the capacitor) and ESR or effective series resistance. Leakage really needs to be measured at or near the working voltage, hence an old-fashioned Megger on its 250 volt range is a really useful bit of test gear. Measuring ESR is a bit more complicated, but cheap ESR meters are available. The point is that if a reservoir/smoother is anything less than perfect - a common situation in vintage sets - it will need replacing, now or in the future. Best to replace it now, and sleep nights!

One thing I’ve found is that leaky electrolytics often exhibit higher capacitance than the marked value.