How to make krypton gas glow
Great question! I don't believe it'll wear out in the short term. Light is produced when the electron is excited to a higher orbital and drops back down; this is completely reversible. Neon tubes work on the same principle and last for years!
Eventually (probably after many years) a whole bunch of effects will probably kick in; if there's some impurities in the krypton, they might react with the plasma; the walls of the container will degrade and become opaque, etc.
Whether a certain voltage will cause the krypton to glow seems to be a pretty complicated problem! I believe that would depend on the frequency of the tesla coil (V = dB/dT), how it's coupled to the gas (is there a wire in the tube?), and how large the volume of gas that you want to light.