Originally Posted by
mrrabbit
My bet is that your LBS just does a quick insert of the replacement spoke - brings the rim back in line and calls it done.
In other words - they haven't bothered to bring the wheel into spec tension-wise - roughly 20 minutes of additional work.
Which wouldn't matter much unless they replaced all the spokes on the side and stress relieved.
Spokes fail due to fatigue, with the number of cycles survived dependent on cycles (about 750 per mile as they pass the bottom of the wheel and unload, the same for all spokes in the wheel), stress cycle magnitude (your weight doesn't change as the wheel rolls so this is also the same), and average stress (mostly what's left from the elbow forming operation when you haven't stress-relieved with this being about the same in all spokes, with a little from the average tension so all the spokes in the side are about the same).
Once one spoke has failed due to fatigue all of them within that set (front, rear drive side, rear non-drive side) are close to their life limit.
The right fix is to read Jobst's book _The Bicycle Wheel_, replace all the spokes in the failing side(s), correct spoke lines, achieve high uniform tension (use a Park tension meter on deeper wheels), stress relieve, and be happy for the next few hundred thousand miles (you'll need to replace the rims as brake tracks wear out or your crash them and deal with bearing wear).