A lesson I've learned the hard way is to sell progressively. About 10 yrs ago I held $20k in ALK, the price doubled and I sold out and was very happy with $20k profit. The ALK price continued to rise (there was a squeeze on rare earths at the time) and ultimately I left $120k profit on the table. Now days I sell progressively as the price rises and so far this has worked out much better for me.
