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And you have to differentiate between trading and investing, your friend trades because he wants to make money quickly because investing takes longer to see the results and agrees that everything must be done without rushing and never go all in.
Sometimes a beginner cannot distinguish between trading and investing and several types of trading that will be used.
A trader will trade quickly to make a profit, using the scalping method so that every price movement that occurs will make a profit.
This also happens to traders who use the Swing trading method, it will be longer by waiting for the price to break through the bottom support and will sell it when the price touches or breaks through the strongest resistance.
And long-term investments should be used for coins that are intended as long-term investments, such as buying bitcoin and then holding it until the new ATH is reached or the main price target is reached.
And yes, as discussed in this thread, don't use all your capital for investment, do management so that everything can be managed and use a strategy that is suitable for the type of trading or investment that is applied.