Animals minmax on being active. To the point of going into a damaging overdrive when active and repairs when sleeping. The total accumulated wear is massive. Discarding an old animal and booting a new one seems to be more viable than trying to keep the old one going indefinitely.

Just like reptiles, who die from the accumulation of damage, at a time depending on the rate of damage, but their point is that mammals don't merely die from accumulation of damage but also have a built-in clock.

Just like an old chat. Start fresh without so much accumulated contextual baggage.