For the things im making at the moment i have no need for them to continue working longer than i do. If i will not live to see my devices fail with either osc then it doesnt bother me which i use.

I would have thought that a higher speed would shorten the lifespan but i think it depends on what actually fails. If the inner workings of the chip will only last for a certain amount of switching (like some relays can only switch 100,000 before they are due to break) then it would shorten the lifespan (twice as many switches, half the length of time).

That reply suggests that the lifetime doesnt have anything to do with that and it may be something else. Maybe something inside degrades over time?

Just my thoughts anyway