One mans trash is sometimes trash

I've heard all the horror stories about instant on sets supposedly causing fires and short tube life but I have a couple of questions.

Have heard from quite a few people (electronics tech types) that in general, leaving tube sets on often leads to longer tube life (they were speaking of tubes other than picture tubes) because this eliminates the heat cycling of the filaments. Don't know if this applies to picture tubes or not, but is interesting nonetheless. Comments?

My folks bought a new Sony KV-1701 back around 1972 that had instant on which I used to leave in the on position. Put a LOT of hours on that set and it lasted 10 years. Go figger. I know there are always exceptions to the rule, perhaps this was one of them?

The other thought that occurred was concerning AC versus DC currents. I've always understood that light bulbs last far longer if they're run on DC current as this avoids the whipping motion that the filament would see if AC were supplied. There are all sorts of small rectifier devices that you can install in a bulb socket or inline with a lamp so that you end up with DC.........pardon my ignorance, but what do picture tube filaments operate on? I guess you all see where I'm going with this. Assuming for a moment that they normally run on AC, could supplying DC as the instant on power perhaps be the best of both worlds? Obviously a circuit would need to be designed to prevent feeding this DC back into the chassis when the set was off.

Then again, am most likely over analyzing the situation! LOL

Anthony