performance can be complete, substantial, or inferior. if the parties perform exactly as agreed, you have complete performance and no breach of contract. if a party, in good faith, performs substantially all of the terms, confers most of the benefits promises, and the omission or defect is not fatal, you have substantial performance and damages can be award. if performance is not substantial, the non-breaching party is excused from performance and there is a material breach of the contract.