Originally Posted by Dan Winterland
Carbon brakes wear every time the brakes are applied. As they cool after use, the top layer oxidises and this is what gets worn away on the next application. So if you use full reverse on landing, the brakes apply, then the reverse comes in. At this point, the brakes release a bit to maintain the set deceleration rate. When you stow the reversers, the brakes apply a bit more again to maintain the deceleration rate. By using reverse thrust, you achieve the same landing distance, but e=wear the brakes more and use more fuel. In dry conditions, there is little or no benefit in using full reverse thrust. In wet conditions, or worse, the brakes may not achieve the full selected deceleration rate, and this is where greater than idle reverse thrust should be considered to achieve the desired rate and reduce the landing distance.
It does however take a few minutes for the brake surfaces to oxidise; therefore the autobrake modulation during a single landing won't make any difference to brake wear. In fact, on 330/340/380 SOP is to use full reverse to 70 knots. With the 330/340 we were permitted to brief and use idle reverse (when fuel was at it's peak), but for the 380 the BTV autobrake setting requires full reverse! That's because reverse thrust is far more efficient at higher speeds - as I'm sure you're aware, and the brakes only 'kick' in later in the landing roll.
I know it's not 320 but does give a bit more background perhaps
Anyway - if it's wet and kakky then anything that helps you stop should be used and damn the brake wear!