User blog comment:ARZC/Mastering the devil fruits/@comment-3119203-20120308031412

I think that the admirals and Whitebeard had a good grasp of their Devil Fruit's abilities and limitations. I also think that Luffy has gotten his fruit down excellently as well. The Gears are something that most people would not have considered, and the fact that Luffy has them means that he knows his Devil Fruit well.