Carbon Fiber vs. Aluminum
There's no reason to worry about carbon fibre durability. I'm riding on a 20 year old Specialized Epic Allez (CF tubes with Al lugs), and it's just as light and stiff as it was when new.

If you have a serious accident CF may break in a non-repairable way, but the same is more-or-less true about aluminium as well, although it may take more of a tumble to break it. (In theory Al can be welded, but you have to be very careful, as the welding will wreck the heat treatment.)

At the same time, CF is more expensive. If I would buy a new bike today I would probably get a decent aluminium frame and instead spend more money on the components, rather than an expensive frame with sub-par groupset.