I exchanged after ~500h of printing all different materials.
I posted it on K2+CFS modifications: The extruder and CFS tubes & connections what I did. In the meantime I exchanged also the tubes within my first CFS (the second I have only a view weeks when there was a 15% discount on Amazon) recently and the tube between the CFS exit and buffer enter because it was too long and some filament did push too much into PTFE wall so it bent as well.
When writing this I just printed a part of a ‘magic box trick’ for my other grandson in extrudr NX2 matte black filament.
