The best time for buying is at low price and I think if you sell your coins with profit then you should not regret after Fluctuations in coin price because you have already taken your profit so ready to make another step instead of regret about past.
If you are in doubt about other coin then just buy bitcoin now and don't sell until you achieved your target. This time is not suitable for selling but if someone is in huge profit and he cannot hold longer then selling should be preferred. Understand the market and accept your profit but I think if someone is selling their bitcoin without waiting more so he will miss the opportunity of having huge profit in Bull season.
for me the time you buy doesn't really matters but when you sell, if you have a plan of selling when the value is higher then no matter what you spent during your purchase you are sure of making some profit because you already have a plan and you are committed to this plan not minding what the prevailing circumstances are, and then when it is convenient for you then you carryout your transactions, perhaps this is where the long term approach comes in.
I don't think the mentality of selling Bitcoin after the price increases has anything to do with long-term investment. Because the price of Bitcoin can increase a lot even within 1 year. This does not mean that you have to sell Bitcoin if the price increases within 1 year. This can never be a long-term investment strategy. The price of Bitcoin fluctuates a lot, but after a long time, its price becomes several times higher. That time should be 4 to 10 years or more. As a result, real profits can be made by investing in Bitcoin. Therefore, it is necessary to get out of this mentality of selling only when the price increases and follow the complementary approach that should be adopted to continue investing effectively for 4 to 10 years.
If you decide to sell after buying Bitcoin and get a slight price increase, you will never be a holder and this kind of behavior definitely refers to short-term trading, which is definitely one of the reasons for the loss of Bitcoin. If you are a short-term trader, you will lose and if you are a long-term investor, especially if you can hold your coins for 4-10 years, then the chances of profit will be much higher. Bitcoin can never guarantee profit, but if someone can hold it and accumulate regularly, it is possible to get several times the return on investment. The current price of bitcoin 110000 but it is still good time to invest in Bitcoin, only long-term holding should be given importance.