Each model is different, some can use it , some dont need it, what ever makes it easier, then you can concentrate on more exciting things, like touching the tail! If you do a lot of hovering DOD with different models, you'll get it. It is a preference, not a must, but if it requires less control input to keep it hovering AND it does not affect regular flying much, it's worth the extra effort. There's not a 3-D'er on the planet that doesnt tweek thrust lines,CG,trim ect..,ect...