Frequency/market practice: Fairly common; duty to mitigate exists in common law for contractual breaches.
Is there an exclusion of consequential damages?
Frequency/market practice: Fairly common.
Are provisions that there is no liability if the buyer has knowledge common, or does buyer knowledge have no effect?
Frequency/market practice: Rarely, "anti-sandbagging" provisions (no party is liable if the party seeking indemnification had knowledge) are rarely included.