The usual hilly route - 30mi, ~4500ft ascent - to start off the morning. The hills here are steep and twisty. The road quality is mixed. The steepest descent I had to face is around 12-14% with plenty of hidden driveways (the ride takes place in the morning when people are headed to work). I had to make one emergency stop - CNC caliper brakes on carbon rims - and never once did I think "wow I really need a disc frame!"...
It's really up to you. How comfortable you are in descending. How well you can handle your bike in adverse conditions. It's all up to the individual to be *honest* with their own abilities. If you have, be honest with yourself, fear in descending or sometimes lack confidence/concentration when conditions get averse, you may want to consider disc brakes.
Otherwise... it's this:
Stolichnaya wrote:California + dry + no rain + aero penalty + weight penalty = whole lotta nope.