Originally Posted by bulldog1935

and again, the problem is the use of "never"
Only steel qualifies here. Aluminum and composite both in normal use will eventually fail - almost 99% certain it won't be within your lifetime use - but undamaged, un-rusted steel can be handed down for generations.

To me, the scariest thing is people buying used bikes with carbon forks. If you buy an old frame with a carbon fork, you should probably buy a new fork.