It's worthwhile to invest in the cost of repairing a leaky faucet if it's newer, but it's advisable to replace it if it's over 20 years old. The severity of the leak also plays a big role. Faucets with major leaks are often not worth the money or hassle of attempting repairs. Generally, a new faucet that leaks probably just needs a part tightened, but for an older faucet, it's a sign that it's time to replace it. Other signs you need to replace the faucet include rust, mineral deposits, or old age.