[35Z5]

As fa as I remember, even old Soviet TVs did not need service every several months, and those were used daily, usually in the evening hours, though of course back then we did not spend as much time in front of it as we d now: there was not much to watch. Still 2-3 hrs every day and more on weekends.

I suppose the 85+ TV repair shops listed in the local 1966 yellow pages was just filling space? Many of those had three or four locations. By comparison in the 2005 YP there were 12, phonebook at least twice as thick with probably ¾ size print.

 I said "Soviet TVs". We had 1 or maximum 2 radio repair shops in the city. Not that it was enough....guys like me were sometimes asked to fix a TV. Or a tape recorder.
But the 60-s TVs were very good, most common problem being drying electrolytic caps, scratchy controls and oxidized channel selector contacts.
Later when more modern TVs were introduced, especially the color type with semiconductor voltage multiplier which failed often....yes. But old TVs failed rarely. The flyback driver was a beam tetrode tube, no semiconductors......tubes lasted years. We owned two TVs, first we bought in 1965, worked fine though the channel selector knob broke within 1 year, the second we bought in 1972, also lasted all the way into 1979 when someone gifted us a color TV. No failures. BTW here I had an old Zenith color job, probably end of 70-s model, worked fine until I moved and did not take it with me.

No you said "even old Soviet TV", which implies they were worse than US brands. 

I serviced Sears Warwick by day and everything else by night. Lets just say, a service contract was a good idea. 

I will grant Zenith were a step above most other brands but were not without failure. We had a '54 Zenith when I was a kid. Seems the 5U4G was always bad(I remember marvling at the first 5U4GB pop brought home) and 6BQ6GT Horiz output was notorious for lack of width.