I normally use 4, but when my timing goes to pot, as it sometimes does, I go to 5. When I use four I stand just behind the closest dots to the foul line. When I use 5 I'll move up to within 5 feet of the line and force little steps until it feels right. Then I move back to my normal spot and still use 5 for a while until things feel good, then I go back to 4. I could not possibly explain why I don't use 5 steps all the time.
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"To plunder, to slaughter, to steal, these things they misname empire; and where they make a wilderness, they call it peace." (Tacitus)
"If one tells the truth, one is sure sooner or later to be found out. " (Wilde)