As per request, here's a step-by-step procedure I use to refurb hose bibbs. I'll be using one I've already worked on for the disassembly portion. I usually do this on the bench in the shop, as most people opt to just swap out a new valve. But the refurb can be done with the faucet still attached to the wall. One must just be careful when doing that method - turn water off to the structure, don't get over zealous with your wrenching (back-up wrenches are mandatory), and make-sure you have the proper parts/rebuild kit handy.
Here's a typical water faucet valve, also called hose bibbs (due to the 3/4" garden hose thread on the outlet side) and sill cocks. The first is an Arrowhead brass, the second is a Nibco. The parts will be different but the procedures are very similar.
The parts that take the wear and usually have to be replaced are the seat washer and screw, the nylon packing washer, and the bonnet cone washer (in that order).