I'm seeking input on how decrepit/damaged/ rusty a chassis should be before you consider painting and/or replating. Do you prefer "battle scars" or something nearing pristine on these 30-40s era consoles and tabletops? I realize this is subjective, but it is opinions that I seek.

Well for a true restore replate of course.
That c sense says otherwise. Cost you know.

Depends on what kind of chassis and how bad the rust is. If we are talking something high end like a EH Scott or McMurdo Silver, then it would be worth the effort to re-plate.

But for a lowly, run-of-the-mill radio. I would clean the chassis and maybe use a small wire wheel or some rust remover to clean it up, but doubt I would go through the effort to paint the chassis. I have however repainted rusty black power transformers as they tend to stand out more and are fairly easy to clean/mask/paint in place.

Be very cautious with the cadmium plating on many chassis, especially with rapid rust removal.

On cheap radios, there may not be plating. Here's an example of a cheap radio that desperately needed painting of the chassis. That was easier because it was a kit, therefore screws rather than rivets.
https://people.ohio.edu/postr/bapix/oHopper.htm

-- Rich

+1. Paint only if it's "a labor of love". No practical reason to do it O/W.

Any non chromed chassis I'll simply scrub with Simple Green and a soft tooth brush. After a good long scrubbing, what ever the chassis looks like after that, that's the way I accept it.

Scrubbing a cadmium plated chassis with Navel Jelly will dissolve the cadmium plating, leaving behind a shiny but rust prone chassis.

I typically leave well enough alone if there's just a few inconspicuous spots. If it's an obscene amount of rust (usually a side effect of mice) I'll sand it down, hit it with rust converting paint from an auto parts store then usually "chrome" paint from the auto parts store (which isn't anywhere close to shiny chrome but is a good match for chassis steel).
If I ever come upon a valuable chrome chassis or something something not chromed that's high buck and too far beyond reasonable patina into disgusting rot I might spring for a replating.

I tend to leave sets with reasonable patina looking original and only do cosmetic work when something is extremely messed up...Wood cabinet that all the lacquer is flaking off, chassis that's more than 1/4 rust.

Unsightly rust patches I will paint silver Tremclad with a brush. Then a wipe with a cloth removes paint from the plated areas while the rough patches hold the paint.
As mentioned, I don't disturb cadmium anymore than necessary. It is airborne powder you want to avoid.

Thanks for all the responses. I could not make up my mind on an 8 tube Silvertone console. I know its value isn't great. So far, I've taken a Dremel clone to it to remove some of the rust spots. But, of course, that ruins the unformity of the grunge/patina.

Everything's a trade-off. You have to determine when it looks about right to you, and then stop.