Well yeah, but if complex self-replicating organisms aren't also very good at self-repairing, they don't self-replicate very long. Individuals do get less good

Well yeah, but if complex self-replicating organisms aren't also very good at self-repairing, they don't self-replicate very long. Individuals do get less good at it over time, though. The structures described earlier as "shortening" are called telomeres [1], and they do actually do that, as a result of DNA copying being a physically somewhat destructive process. They're purely structural rather than informatic, though, and everyone starts out with a fresh set. [1] https://en.m.wikipedia.org/wiki/Telomere https://en.m.wikipedia.org/wiki/Telomere