Is there any data on the longevity of the tube when ran continuously? I have a mightyohm kit, but I decided against building a monitor device around it because

Is there any data on the longevity of the tube when ran continuously? I have a mightyohm kit, but I decided against building a monitor device around it because I've heard rumors that the tube quickly degrades if ran 24/7. I don't think I ever saw any kind of measurements that would confirm that rumor though.