If you read the trading literture, most of the wiser traders seem to scale in as it's going up - Bill O'Neil and the like.
If you are sure of the bottom, scale back in. My brain tells me to wait until I've exceeded my entry price, but fear, greed, and all the other emotions enter in and I pay no attention to wisdom.
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Minnesota Fats: "Shut up and shoot pool, Fast Eddie"
Fast Eddie: "I'm shooting pool, Fat Man. When I miss, you can shoot"