A Hitting a pothole may dent a rim but is unlikely to break a spoke unless it is already weakened by fatigue, which is the factor responsible for almost all spoke failures. The best way to avoid spoke fatigue is to go to a skilled builder, who will advise on spoke count and rim weight (heavier rims are stronger…) and use correct spoke tension and proven stress-relieving techniques to minimise the cyclic loading responsible for fatigue failure.
As a rule of thumb, 36 spokes is the minimum count for any 700C wheel expected to carry a pair of loaded panniers; smaller wheels (e.g. 26in/ISO 559) are inherently stronger and you may find 32 spokes sufficient, depending on rider weight. Obviously, it is a good idea to avoid potholes where possible.
Cycle’s Technical Editor