First some context: I am considering building a decoration out of a old RF power vacuum tube (like a Eimec 3-400Z, Telefunken RS630,...) with direct heated tungsten filament. I plan to get a appropriate SMPS to power only the filament for a nice glow in the living room & already know what to look out for as to not burn down things (already built a tube audio amp from scratch).
Since I don't want to actually drive the tube with a signal, no high voltage is necessary (plus I wouldn't put 3kV into my living room). This also means I likely don't need to worry about heat, e.g. the 3-400Z would have a plate dissipation of typically 400W when used in a power amplifier.
My question: I found that there are claims of tubes decaying faster if only the filament is heated an excessive amount of time; I wonder if this will cause the "light" to break quickly, or if it doesn't matter since it will only degrade the characteristics (German "Kennlinie")?
I found the similar question I need a basic primer on interpreting vacuum tube datasheets - but even if I only would turn the "tube light" on for decoration a few hours per week, I suppose I will operate it way longer than they shot that movie.