The kitchen faucet is the most use faucet in the home. Eventually the faucet will begin leaking after years of use. When this happens you will need to make a decision on whether you should repair or replace the kitchen faucet. The average cost to repair a faucet is approximately $250 to $300 and the average cost to repalce the faucet is between $350 and $500. The repair costs are expensive because most faucets are repaired by replacing the cartridge which alone costs and $between $80 125. So once the faucet begins to leak and waste water, you would make that decision based on the quality of the faucet. If it's a regular faucet lets say around $100 it might then be cost affective to just upgrade and get a new faucet that will last another 5 years or so.