General rebute
Hector rex.
Doesn't count. He received his implants as a child/teenager.
Luther
As I remember, Luther was remarked as being weaker than an average Astartes. Smaller in bulk and thus strength. Kor Phaeron was also scorned as "half-astartes". As far, I had received 3 names and all three names were incorrect in their assumptions. Some received modifications as children, some were remarked as smaller Astartes. After their fall to Chaos it is pointless to compare their strength to regular Astartes as Chaos Gods can twist reality and make them as big as they want to be. After all, mere humans blessed by Chaos can grow bigger and stronger than Adeptus Astartes in power armor, but that doesn't really mean anything.
In the Night Lords series, its mentioned that to them, it has only been a few hundred years since the Horus heresy, do to the effect living in the eye of terror.
Time doesn't pass in the warp the same way it does in real space, thus heretic astartes can live way longer than they otherwise would have. That's not a contradiction. It's not even inconsistent. That's been in the lore for as long as I've been aware of it. Chaos Marines don't live longer, time is just relative.
Granted, but in the warp time is relative. Why you all are focusing on cases where warp had shortened period rather than thinking of a cases where it had lengthened? An individual can just as well live 1000 only to find out that it only had passed 100 years in realspace/elsewhere. While there are times when space marine time in a warp is shortened, other times it is lengthened. Time warping phenomena is not consistent and it can take relative and physical forms. Relative in terms of warp travel. Physical in terms of living where time passes by slower.
I do not have specific examples so I can't state anything. Yet, by same extension, if it is not stated otherwise, a veteran of an old war is at least 10,000 years old. He might be younger or older, but with warp you can't say for certain if it had extended his lifetime or had shortened. I'm not familiar that Abbadon is said to be younger than time he had lived, though I would be happy to be corrected at this point.
For Spetulhu
Except for the fact that (loyalist) marines living to 700, 900, 1100 are all great legendary heroes, not something you see every day. A marine living longer than that is either a fluke (he's been in stasis or whatever) or he's a dreadnought, which means he's usually kept in stasis until needed. There is exactly one non-dreadnought Ultramarine older than Chaplain Cassius (who is 400 or so) and he's called Roboute Guilliman, Primarch returned. Marines are warriors, becoming one is hazardous, their entire life is dangerous. 90% of them will get rokkit-to-the-face syndrome before hitting 200.
Crippled marines are put to training the next generation, but the fluff doesn't mention a legion of Heresy-era drill sergeants whipping the new recruits into shape. So even these crippled sheltered-job guys do apparently die natural deaths at some point - which is supported by the fact that marines in general lose body parts and get scars. Their bodies can stand a lot but can't repair all damage all the time, it adds up and at some point they must die.
The issue with Space marines is that they do not retire. They die in combat one way or another. I know of cases where space marines in dreadnaughts being in perfect bodily condition even after thousands upon thousands of years, but their minds being at the brink of insanity or giving up. In a story it was remarked that psykers are somewhat resilient to this aging. This would align with what I had said about Chaos space marines. Their bodies are as deadly as ever, but their minds are one of a senile old man. Constantly somewhere far away in its memories rather than here and now.
For Andersp90
What?
This was in regards to Sigismund aging and being weaker. Well, death of Sigismund was supposed to be as an epic for loyalist as had truly glorious death, as it was supposed to hype up Abbadon and make Chaos fans happy. When author uses excuse "oh, and he only had beaten him because he was an old space marine. He totally would had kicked your ass otherwise" just sounds like downplay and disrespect to other faction which also needs to look cool. This is especially more insulting then one of the mightest space marines ever lived, one who killed single handedly primarch can't be given a fair shot at Sigismund. Even when Abbadon had given his life to kill Sigismund (He had given one mortal strike for Sigismund in order to create opportunity to allow his claw to feast upon Sigismund's life).
"Dante sighed and reached up for his helmet. Sorrow troubled Seth’s boundless, caged fury. He disliked Dante hiding behind the face of their primarch, but once his helmet was free, he liked what he saw even less. Dante was old. That was what nobody ever expected to see behind that ageless, golden face. They thought him in the prime of his power, such was Dante’s reputation. But men were not meant to live so long, and Dante, though exceptional, was no primarch. Shadows pooled in his sunken eyes, a morbid foretaste of his appearance in death."
I acknowledge your point, but I simply find that this aspect is not woven into lore. There are scant references of space marines aging, but in most cases, lore doesn't care about age of a space marine. Psykers and Chaos all together ignore aging problem while other heroes can be of varying age and have no difference between an youngster and grandpa space marine.
For LordofHats
Well, he has been jokingly referred to as 'failbaddon' so I won't even argue that. I feel like at some point Abby was so BA in the fandom, he became the guy that got thrown in to then show how BA others were and this resulted in Abby falling afoul of the Worf Effect as time went on.
I understand that community loves to joke about Abaddon. Though, if we take lore seriously,
GW for a long time was trying to rehabilitate Abaddon and his achievements are appraised in multiple stories. I want to take W40k lore as seriously as it is possible to take it and having comedy relief figure just degrades an entire setting as a whole.
Space marines very clearly age. Whether or not they can die of old age is kind of unclear, but they very evidently age.
Indeed they do and I can't disagree with that. I just dislike it. I can disagree however on a point if space marine psykers age normally. Also, if Chaos space marine age normally.