Since I started building my own wheels over 20 years ago, I've never broken a spoke. I do 2 things: use a Park TM1 tensiometer and double-butted 14-15-14 (2.0-1.8-2.0) spokes. Double-butted spokes are much less likely to break and they put less stress on the places where they commonly break. On our tandem, I use CX-Ray spokes and also never broke one. It's my belief that heavier spokes are more likely to break, not less. When I wear out a rim with my rim brakes, I lace in a new rim using the same spokes. I'm slow, so it takes me a couple hours to do that.
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