While an adjustable wrench might work for some accessible nuts, a basin wrench is highly recommended for faucet supply lines. Its long handle and swivel head are designed to reach tight spaces under the sink, making disconnection much easier and preventing scraped knuckles. It's worth the small investment if you plan on doing more plumbing DIYs.

The most critical step is to completely turn off both the hot and cold water supply valves under the sink *before* starting any disassembly. After turning them off, open the faucet briefly to drain any remaining water from the lines. This prevents unexpected leaks and potential water damage when you disconnect the supply lines.

The cost is usually minimal, often just a few dollars for replacement O-rings, washers, or a cartridge (typically $10-$30). While classified as 'beginner,' the difficulty can vary depending on faucet accessibility and component type. Expect potential frustrations with tight spaces, but with patience and the right tools, it's very manageable.

First, ensure all connections are tight but not overtightened. Recheck that the correct replacement parts were used for your specific faucet model, as slight variations can cause leaks. Sometimes, the faucet body itself might be corroded, or the valve seat needs attention, potentially requiring a full faucet replacement if repairs aren't effective.