Should powering TV set on and off be done sparingly?

Factual Questions
1

A few judicious Google searches, as well as a search through the Straight Dope archives and snopes.com failed to shed light on the following:

When you turn a television set on and off, how taxing is it on power/electricity, the lifespan of the TV, the environment, or anything else along these lines?

I ask because my mom protested to my dad turning off the TV and suggested that he simply put it on mute, even though we neither need nor desire the TV to be on for the next hour or more and would like the peace of a room without sound or moving pictures. According to a friend of a friend of my mom who is allegedly knowledgeable on these matters, excessive powering on and off is bad for the set. I, on the other hand, was of the opinion that the TV works for us, not vice versa, and I think that it’s unlikely that there would be any economic or environmental repercussions so great as to warrant such excessive pandering to a lifeless machine to the detriment of our own comfort.

What’s the straight dope?

2

If you’re not going to use it, turn it off. True, turning it on and off repeatedly stresses some components, particularly the filaments in the CRT, but by the same token leaving it causes wear on other parts. The debate over which is worse, cycling stress versus wearout could go on for pages and pages with no definitive answer. The bottom line is, if you don’t need it for more than a few minutes, turn it off, since that will unquestionably save energy.