Wow, good discussion here. Let me underline that I do not claim that my ideas are well thought out (or even thought out at all), this is pretty much all just background colour for me.

Me:
>     > 2) Serious (physical) injuries. For purely thematic reasons my
>     > auto-docs come with a dozen lights on them, each green/yellow/red.
>     > Recovery from three red lights (or some appropriate combination) is
>     > very very rare.

Rupert Boleyn:>     These are something that I assume can be pretty much completely repaired
>     at 'sufficient' tech levels. If all else fails they can just grew a
>     cloned replacement limb or organ and swap it in.

I agree with this, however, for simple game-playing reasons I suggest that there is a limit, otherwise people in the TU are effectively immortal, providing they get to an auto-doc in time.

One limb shot off, usually not much problem providing the patient doesn't bleed out.

Two limbs: bleeding out happens faster, plus just "more stress on system" in regrowing both of them (and extra recovery time if you do survive).

Three limbs: and so on.

I stress that I do not claim that this is canon, but as a GM I want Traveller combat to be nasty, dangerous, lethal, and best avoided if at all possible. You may choose otherwise.

>     The exception is major
>     CNS damage - drugs to encourage nerve regrowth plus lots of therapy will
>     *usually* bring back full function, but any memories or skills lost to
>     brain damage are gone - skill can be re-learned, but memories that are
>     gone, are gone.

Yes, I agree. Worst case you end up with a baby in an adult body, which is, um, tricky.

Me:
>     > 5) Excessive cold-sleep - let's say more than 10 years continuous
>     > (vary this number as you might think appropriate). Crews engaging in
>     > long-term repetitive cold-sleep will tend to 'be under' for (say)
>     > three months at a time, followed by 2 weeks fully awake, repeat as
>     > necessary. The higher the TL, the more the down-time can be extended.

Rupert Boleyn:

>     I see it the other way - it's the freeze-down and warm-up processes that
>     put wear on the body, so it's better to leave people in for a long
>     single stretch than to cycle them over and over.

Interesting thought. Of course the downside is that the person in cold-sleep is completely offline. My approach lets them be around sometimes, to dispense wisdom, lies, travellers tales, and so on.

>     Then you get those socialist hell-holes with fully socialised
>     health-care, but they're boring so Travellers don't go to those.

Chuckle.

Alex Goodwin:>     Looks like you're assuming golden age (from later on in your post) -
>     where do human races with predispositions to longevity (eg pureblood-ish
>     Vilani, Daryens, etc) fit in?

FWIW I run my own highly variant TU in which I am happy to make as many non-canon assumptions as make sense to me. That said, it's a good question which I have not thought about.

>     Given old age being considered a disease/disorder, where do senolytics
>     (medicines that clean up the debris of metabolism aka aging damage) fit in?

Senolytics aka anagathics? (James Blish, I think.) Again, without thinking about it too much, I'd suggest that if you have those then they are all part of the normal medical care system. You hit a body age of (say 50), and you get started on those drugs. Like getting a colonoscopy these days.

>     IIRC, there's seven major classes of aging damage suffered by us
>     baseline Terrans (the ones that happen fast enough to knock us mob off
>     today - there may well be more, but we keel over too quickly for those
>     others to have an effect).  Cancer is only one of them.

And Grandfather et al may have genetically engineered the Vilani for long life, fewer fragile genes/gene complexes/cancers, etc, etc.

>     > 3) Infection by 'hitherto unknown micro-organism" from
>     > "un-/under-explored planet X". Again, purely thematic.
>     Always a good way to keep the pot stirred.  At a polity level, wouldn't
>     the enforced quarantine of Jump (over millennia) select for nasties with
>     long latent periods?

Probably true, although an occasional breakout likely happens.

>     So you're handling the radiation damage inflicted by the cold-sleeper's
>     own body to itself?  Would make for some interesting Frozen Watch shenanigans.

I handwave radiation damage, to be honest. Too much paperwork :-) EG no radiation in JumpSpace, and ships in RealSpace have significant electromagnetic fields to deflect such nasties. Otherwise, dragging this back to RL for a minute, no-one is ever going to spend any significant time outside the van Allen belts. I'm happy to accept that there are easy fixes for minor genetic damage. Perhaps everyone gets a complete scan of their DNA / epigenetics at birth, and part of your standard annual physical checkup is to get another one, and then injected with some virus which resets the DNA back to the original. Handwave time, again.

Me:
>     > 6) Some types of genetic fragility - I'm thinking of things which
>     > would express _in utero_, before it's possible to pop the foetus out
>     > and stick it into an auto-doc. After that things like CRISPR/Cas9 with
>     > a few thousand years development can take care of pretty much anything).

Alex Goodwin:
>     Following along the "few thousand years development", wouldn't the
>     capability to _fix_ most cases of that imply being able to _screen for_
>     such cases, ntm risk factors leading to it?  In our timeline today,
>     genetic counselling is available for such wonders as sickle-cell anemia,
>     Tay-Sachs disease, etc - that capability would probably advance in parallel.

Yes, I agree, but these things happen. Horny teenagers, backward planets (the kinds that Travellers *do* tend to visit :-) ), and so on. Again, this is background colour to me.

Me:
>     > uterine replicators.

Jeffrey Schwartz:>     T5 says you can grow clones either in fast-grow in a tank, or slow
>     grow in a tank I suspect that counts as uterine replicator

Good point, thank you!

Alex Goodwin:
>     Why would it have to be the same across one planet?  Frinstance, noble families
>     might have some private area for their demented geezers, while the hoi polloi
>     have to settle for nursing homes.

I think we can guarantee that that sort of thing is *definitely* going to happen. Maybe not with dementia but with medical care in general, and everything else. Otherwise, what's the point in being rich? :-)

Jonathan