The wear items are the cogs. The body will last longer than any other moving part on the bike, with a modicum of care. That goes for the ball bearings as well, which are at any rate cheap to replace, in the unlikely instance of needing replacement.
Of course, the internal lubrication cannot be expected to last forever, this comes under the "modicum of care" proviso.
For some C&V enthusiasts, it is practical to dismantle and overhaul freewheels, and for others, it is more practical to discard and replace them.
