From The Fort.

So, backing up, many people say that they suddenly "feel their age" around 30 because their body, if they keep using it like they're 20, will stop healing faster than they can hurt it. Many chronically ill folks deal with this slowed recovery starting at a much earlier age, and more dramatically. When we die of 'old age' that's in large part due to your healing factor being slowed down so much, the act of being alive wears you down faster than your body can heal.

Robots can not heal.

Sure, they can have parts replaced, but all mechanical parts are installed with an expected number of uses and hours of operation, not even accounting for any traumatic damage.

These legs are rated for three years of use, or 20,000 miles of walking. I'm one year and 3,000 miles over, and can no longer hit my top speed, and tend to veer left if I'm not careful.

These eyes were supposed to be good for 5 years, but the bright lights of the desert and the frequent sand storm mean that after two years in, some of the sensors are burnt out, and the lenses are scratched and difficult to replace, and the same thing is just going to happen to the next pair, so is it really worth it?

My oil tank is cracked, and until I get a new one, I need to drink a new bottle every morning instead of every two months, and I can't bend over forward without spilling some.

This heart has 3 million beats in it. At 60 bpm, that will last me over 11 years. At 120 bpm, it won't last six, until I need a new one.

My CPU was made to last for 5 years with average use. At 3 years, I can think at 65% of the speed I started with. How slow do I have to be before it's worth it to replace that? Every robot is built dying in a way that a healthy able bodied person cannot fully understand. The idea that every part of your body is ticking down, that taking a rest day only delays the inevitable, that once something is broken, it stays that way until you can get it fixed.

Sure, some cars are brand new, owned by someone with a garage and nearly infinite money to pour into upkeep. Some of them are old beaters that are just trying their best to get their 20-something owners to class and back, desperately hoping that it can hold its timing belt together until they can afford to replace it, but please drive slow until then?

Do you think that old beater car might also be worried about the day it becomes cheaper to replace than maintain? That "being bale to afford it" might refer to a new car, not a new belt?