Maximum number of competitions ?

I know this is an old post but what is the maximum number of races needed for each sprint event? I’ve heard 10 races for the 100, about 6 for the 200 and 4 races for the 400. Any thoughts from anyone? And what about the short and long hurdles?

There is also a post somewhere in the archives where Charlie talks about number of 110mh to a peak … can’t recall that number though, maybe you can find it.