Too early to say for sure, and it'll still depend on prices of the new unsold 24-70's on the market. If that goes down, the prices of the used ones won't go up. What will it be in a few years? It'll be a definite downtrend years down the line (matched for inflation), but for the current time, i don't think there will be marked changes in the price of whats being sold on the used market...