How do I fix a leaky faucet without calling a plumber?

To fix a leaky faucet, first turn off the water supply valves under the sink. Then remove the faucet handle, usually by unscrewing a screw hidden under a decorative cap. Once the handle is off, you'll find either a cartridge, ceramic disc, or rubber washer depending on your faucet type. For most drips, the culprit is a worn-out washer or O-ring. Take the old part to a hardware store to find an exact match, replace it, reassemble everything in reverse order, and slowly turn the water back on to test. The whole job typically takes 30 to 60 minutes and costs just a few dollars in parts. YouTube videos for your specific faucet brand can be very helpful if you get stuck.