n2 The plaintiffs claim the court erred in finding a material breach because the evidence established that VOCC exercised good faith in enforcing Randall's noncompete agreement, and because Jerry's formation of V.O.C. Concrete was undertaken to mitigate his damages from Nuckoll's cessation of the monthly payments. Nuckoll's affirmative defense, however, was based only on Randall's competitive conduct. In fact, the other alleged breaches--the plaintiffs' failure to enforce Randall's covenant and Jerry's formation of a competitive ready-mix business--had not yet occurred when Nuckoll's suspended its installment payments. Therefore, we need not concern ourselves with those breaches, as Nuckoll's affirmative defense must succeed, if at all, on the strength of its assertion that Randall's breach of his covenant not to compete was also a material breach of Nuckoll's noncompete agreement with the plaintiffs.