How do you make your decisions on when to take profits from short-term investments when it seems inevitable that a stock will soon take a dip?

I'm holding some short-term RKLB, and I'm expecting that its previous pattern will repeat, and after this current rise, it'll take a (hopefully) temporary downturn before going back up.

How do you more experienced investors handle these situations? Do you let stocks rise and fall and keep putting money into them with the expectation that they will continue, over time, to appreciate, or do you take the short-term profit and pay the higher tax, buying in when it levels out and begins to rise?