It's not all luck...I do many days of DD on any stock I buy. I read at least 2 years of filings, if available, read message boards, etc. I probably understand more about a company than most of its employees by the time I buy into it.
If I'm not confident it can be a 10 bagger, I don't invest in it. Then, I just sit back and observe, as DD is a constant thing. If things change significantly, I may reevaluate my position, but I'm pretty stubborn about giving up, if the DD still holds.
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