Unless you're a water bear your DNA accrues continuous and irreversible damage throughout life. End of the road is either cancer or senesence as an attempt to arrest cancer.
Edit: Can't believe I forgot the third option, cell death.
Here's some info from Dr. Rhonda Patrick and Dr. Judith Campisi when they got together for an interview.
> As our cells accumulate damage, which naturally happens as we age (even as a consequence of energy-generating processes and immune cell activation), there are only so many outcomes that we can expect. The first possibility is that the cells can die. The second is that they can become senescent – where they stop dividing, but stay alive, all-the-while secreting molecules that influence surrounding tissue. Or, the worst of all possible outcomes, the cells can go off the rails and become malignant.
> "Anything that persistent damage to the genome will drive cells into senescence. It makes sense because that puts you at risk for mutations. Mutation puts you at risk for cancer, so the cells want to shut that damaged cell down." - Dr. Judith Campisi
Also, there isn't just one kind of DNA damage or DNA repair. Different kinds of damage have different orders of badness of effects and have different priors of happening by our cellular machinery.
It was probably something Dr. Judith Campesi, a pre eminent senesence scholar, wrote.