If you are an investor, then you shouldn't be asking this kind of questions on how long should we hold. This question is for traders, because they focus on selling on shortterm. As an investor your goal should be holding Bitcoin for a long time, maybe 8 years and above, therefore stop tweaking for Bitcoin price movements in the short term. Even as an investor it's a joy to watch Bitcoin performing well in the markets, especially when it broke a new ATH last year. But if you understand Bitcoin enough, you will notice that after a long bullish momentum, it will dip again, as a result of macro factors, or big institutes selling of their holdings. You have to be patient Tbh, what you should focus is accumulating more Bitcoin if you have their capability to do that. Your goal should be trying to hold to your targeted time frame or period.
In fact, during the period that Bitcoin price is dropping, investors are now looking for more money to accumulate more Bitcoin because they know it is a big opportunity. When this period is over, what we will likely experience next is a bull run, where the price of Bitcoin and other coins continues increasing and probably sets another all time high.So, for an investor, it is a period to seize the opportunity and increase their portfolio. The only people I may say panic during this period are newbies who are less experienced in the market. But still, it is all a lack of knowledge that usually leads to panic because, if there is knowledge and someone has built confidence in it and is really following the right steps, they will hardly panic during this period.
What really causes panic is when someone invests money outside of their discretionary funds because they already have plans for those funds in the near future. But when it is the right funds that someone invested the money discretionary funds they will hardly bother when the price is dropping because they know that the price of Bitcoin will eventually recover and they don't really need the money at that period of time.