In my experience: once My Butt got used to my first Brooks (B17 Champion Narrow, after about five hundred miles back in 1970), every other Brooks I've had since (Conquest, two Team Pros, B17 Special) have not taken anywhere near the time to break in - which leads me to the conclusion that it was My Butt that got broken in, not necessarily The Brooks.
FWIW -
- Wil