Overtime History has affected Bitcoin value by a significant price fluctuations, market crashes resulting in a substantial loss for sellers and affecting their investments. Looking back at some historical events that occured back in time, most necessarily the Mt. Gox hack that happened around 2014 which med to a total decline for most Bitcoin holders and thus affected Bitcoin sellers during that time.
Meanwhile amidst all, the Bitcoin space has shown a wider proximity and strong commitment why it surpasses all of this challenges and still flourish regardless and why we need to hold. Hence it's a financial mistake and unwise to sell your assets like Bitcoin and go broke in the future.
The Mt Gox era is what I can refer as the stone era of bitcoin and thanks goodness bitcoin survived the 2014 hack. This company operated only between 2010 to 2014 and closed after being accused of theft of million dollars worth of bitcoin, being the bitcoin exchange used by many bitcoin traders then.
However this proves the strength of bitcoin after surviving that era and maintaining its positive trend later on. Selling your bitcoin at anytime exposes you to running at loss or going poor later. This is because even as bitcoin is volatile, it still has records of maintaining a cumulative increase in price over time.

This chart shows how positive bitcoin has been overtime in history. Bitcoin first experienced it's worst decline in history during the 2014 hack before later regaining itself back 4 years later setting an all time high which was unbelievable as at that time. This has been the way of bitcoin, the hope in bitcoin and the future is high and it not what anyone would like to risk for something less. No matter how tempting bitcoin price seems to be today, holding it a little longer would still pay off better. The closing price of bitcoin in 2024 was tempting too at over $76k which was even an ATH as at then before it finally crossed the $109k ATH in January this year. This has been the trend, we have recorded an all time high of $124k on the 14th of this August. Even though the price is declining, holding your bitcoin is still the best option.
As an investor, your plan should be holding for at least 4 to 10 years and this does not mean that you must have to sell off after the period because the longer you hold, the better chances you have to make more gains in bitcoin.
Things are changing and will continue to change for thr better many of us are no longer moved by CEX falling and FUD like before.
Be careful not investing all your money on bitcoin and when the market is down you have no than to sell in loss even while being aware it will profit you HODLing in the long run. This is among reasons emergency funds are important.
Also, it's not bad to sell ones bitcoin. If you think it's time to take profit go for it and don't regret it when it surge so high years later and you then disappointed thinking of your past accumulation.
This is another reason why you should consider if taking profit is worth it at the time you do, keeping yourself in check. You're very right. It's not just about taking profit, it's about taking a calculated taking of profit of which you may be caught in the web. Bitcoin is volatile and no one can determine the new prices at any point. You may sell off today thinking you are taking profit, just to run a loss in the next moment when price goes higher than you have sold your bitcoin. I would suggest that as long as you don't have any serious need to sell your bitcoin, then don't sell. And if you must sell, try not to sell all your bitcoin at a time, and always buy whenever you have some discretionary income.