Since I first got Machak, I have changed the following:
-- steel forks replaced carbon
-- aluminum seatpost replaced carbon
-- Schmidt dynohub replaced a plain ordinary front wheel
-- Shimano freehub replaced a Formula hub
-- 48/36/26 chainring replaced 52/42/32
-- aluminum crank arms replaced carbon
-- Brooks B17 replaced whatever was on there before
-- a short stem replaced a long one
That's all I can think of at the moment, but Machak is a custom-built sport touring bicycle and was not only custom-built, but just about everything has been customized.
Next we'll likely go with a pair of full touring bicycles.