Depending upon the states even the law enforcement differs. Each and every state has its own policies with Non Compete enforcement. The court expects a valid reason for this. If the entire business or part of it is getting some issues then they can consider the situation. I don’t think there will be a major issues with respect to changing a job from one company to another. This link gives the brief explanation of non compete clause enforcement.

https://en.wikipedia.org/wiki/Non-compete_clause