I ride the factory chain grease until it starts to get noisy. That can be around 100 miles. Then I wipe it down with Finish Line citrus degreaser on a rag, followed by a dry rag, followed by R&R Gold, followed by a dry rag. Repeat once the chain gets dirty or noisy.
In the pit at today;s race, I was speaking with a team mechanic. They are all on board with wax. They know the chain lengths of every rider's bike. They strip new chains, wax them, and put them in a bag with the rider's name on them. When the chains get dirty, they change them out with a new one.