We can test cathodes for their performance with over-stress conditions of heater voltage, switching conditions and heater-cathode insulation voltage.  We carry this out in small dummy tubes. Typical over-stress life testing conditions for oxide cathodes are:

Heater voltage: 7V Heater-cathode insulation voltage: 450V Heater on time: 110 minutes Heater off time: 10 minutes Time of test: 2000 hours

We can also test cathodes for emission properties in the same small tubes by varying the amount of cathode current drawn during the life test.