You'll be fully aware then that a meter or two either way on any antenna can mean the difference between signal strengths. That's the main issue in that a long run in one situation can be fine where as another a bit longer/shorter can be the death of a network.
I was in no way suggesting that every run over 50m will have issues, but instead suggesting that longer runs can be more susceptible to issues caused by equipment that we generally think of being benign. The longer the run though the more likelihood there is in being interferred with.