How long should I expect to be able to use a new 5nm CPU (at reasonable temperatures) before these issues are likely to make it fail?

All of the desktop/laptop CPUs that I currently use are 14nm, and I think the oldest is around 7 years old and still working fine. In the past I've tended to use personal machines for around a decade, and I don't really have any desire to move to a shorter cycle. Better battery life is great, but most things are already plenty thin and fast.