the general concept is : don't time the market because no one can.
Warren Buffett, an iconic value investor, said : "Be fearful when others are greedy, and be greedy when others are fearful.” Is that timing the market?
My personal experience is we need both: time in the market and timing the market. Timing the market has two legs: buy dip and sell high. The first leg is relative easy because there is limited room how low the market can go down. You can start to add more positions when it drops 20% and load more when it drops more.
the hard part is the second leg: when to sell? Obviously you can sell when the market is back to the previous high. But often the market will go beyond it. If you keep holding the extra loaded positions, the risk is building up as well. Currently, I don't have a good idea when to sell. Any thoughts are appreciated.