we should define the "unit". Say, how many tick as one Unit.
If there is One Unit fall, we should cut some. another unit fall, we cut more.
If there is one Unit up, we buy some, another unit up, we buy some more, (of coz we need to define how much we wanna buy, depending on the risk management.)
myself always buy or sell using this way.
I believe some ppl here in this forum also .
分期分批买，分期分批卖。
never say , 如果跌就cut, 就不该买。这种话是假设在你100% 确定你的判断上的。在市场里，你总有时候判断失误。你要在自己失误的时候，订好撤兵的策略。
好像战争一样，破釜沉舟不是每个时候都可以的。破釜沉舟的人不容易stay longer at the table.
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