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.
regrets after selling Bitcoin mostly happens because no one can perfectly predict the coin market.
Prices move up and down it's just based on supply demand and sentiment.if after buying,the price goes down immediately just wait untill it's goes up if you are not urgently in need of money at the time,you just can't predict this things.but it's always save to buy coins when the prices drop .
It is important to always be aware of your investments, as well as to invest for the long term. If you pour all your money into investing and are afraid of the ups and downs of Bitcoin, you will be in trouble. Hoping for quick profits can be a source of regret for you because Bitcoin is capable of increasing your wealth in the long term, although there is no guarantee of this, then you can consider the beautiful history of Bitcoin, the history of Bitcoin will introduce you to those people who are currently regretting their mistakes and greed and among them were long-term investors. Many people in the past knew about Bitcoin but they could not have imagined that the price of Bitcoin would be like this in the present time and that it would become such a popular currency. On the other hand, many investors invested in the past, but some investors who saw their wealth increase in the long term as Bitcoin started to grow, sold their Bitcoin greedily. There were also many investors who had full faith in Bitcoin. And by leaving greed and fear behind in the long-term journey, they have been able to achieve their long-term success goal with Bitcoin, so they have been able to multiply their wealth several times over today. However, if you think investing in Bitcoin is backward, then you are wrong because Bitcoin is cheaper now than in the future.