[old_tv_nut]

It depends on the quality of the CRT plant (cleanliness, degree of evacuation) as well as on the quality of the cathodes. These things varied from maker to maker.

IIRC, at one time (when viewing was mainly the three major networks), TV makers figured 2000 hours per year average use, with an average receiver life of ten years. Some of the crappier CRT plants (e.g., Admiral) would produce color tubes that had a significant percentage of failures in the first two years.