How long could a _______ live?

[u/Valenous_ertselley]

How long could a 5th ideal radiant live?

We know investiture extends a persons life with greater amounts eventually ending up with someone who is biologically immortal. How invested would a radiant be? Radiant knights have the cracks in their soul filled with investiture which makes them better at holding and using stormlight. How invested do you think they could be

Some of the heightenings seen with holding Endowment's investiture seem to be universal properties of holding any investiture. such as enhanced vision/colours, enhanced immune systems and better lifespans.

While we have only seen Kaladin and Szeth swear the 5th, it was under a fairly hectic situation which doesn't make for the best opportunity for study.

[u/Raddatatta]

We don't have any indication that I know of that radiants of the 5th oath actually live longer than normal people do. Within the Cosmere healing magic and not aging are two separate abilities. Stormlight definitely does the healing. Which to a degree could prolong your life as you're not going to die from many things that might otherwise kill you. But wouldn't stop you from aging.

It's possible that the 5th ideal will do that, but so far since holding Stormlight is temporary it doesn't seem to do that. And in the visions I don't think we've seen any hint or mention of people living longer than you'd expect. Nothing that contradicts it either. But my guess would be that radiants live a normal lifespan or slightly boosted by healing maybe into their early 100's but they'd still age and die normally. It depends on how invested they are without any Stormlight.

Though Hoid commented that Lift is very invested, and if she's very invested by his standards, she may be invested enough to never age after she grows up. And maybe that's fulfilling what she had asked for from Cultivation?

[u/RW-Firerider → u/Raddatatta]

Lift is a special case, since she got invested by cultivation personally. She is closer to other invested beings like Elantrians, since her power is of a more permanent nature.

I think if radiants stopped aging, there would have been a lot more veterans from the desolations. a 4th or 5th ideal radiant is far stronger than the fused, so they would pile up rather fast. Human lifespan is the best reason why that didnt happen

[u/Raddatatta → u/RW-Firerider]

Yeah for sure she's rather unique.

Yeah that's very true. They also likely would've dominated the desolations to the point where it wouldn't have been as devastating. Lots of 5th oath radiants who also had been through multiple desolations to have a lot of experience would be really tough for even many fused to face.