>>11455834Try to imagine designing a complex machine that could run forever without ever breaking. It's not an easy task. It's much easier to design something that works for a while and then breaks down. That's how things worked out in evolution. A design needs to be pretty much flawless for it to last forever without anything important breaking, and life is absolutely not perfect.
Most signs you can think of for old age are just body parts wearing down or breaking. Cells stop dividing properly, the body stops producing pigment for hair, the joints have growths that cause pain, tendons stretch and break, etc.
