I thought erroneously that I was about to escape the hell of internal cable routing by going Di2 wireless, but I forgot that obviously the brakes are still cable actuated. And internally routed. And with modern bikes, the rear brake may be near the BB and partially covered.

Do you folks who have purchased such modern TT bikes with internally routed brake cables, replace your own internally routed brake cables? I have experience routing shifter cables internally through a difficult old Cervelo frame so I'm sure I can do it, but I'm not looking forward to it.

And yes, I know about and have used the liner-over wire FIRST before pulling the wire so you can use it as a sheath for the new wire. That can also be tricky, or impossible in the case of my old Cervelo when the Jagwire 3mm liner was literally too large for the entry and exit hole. Or, there may be some tricky twists that are just hard to push the liner around.

Or have you not even thought about doing this? (I'll be the first to admit that if I were starting tri now and bought such a bike, this wouldn't even remotely be on my mind for years...which may or may not be fine!)