if one is into Long term Bitcoin investment and maybe he has hodl for 5 years and wants to sell some part of his or her Bitcoin and there's a dip all he will do is wait for it to come up again which is certain then he sell, i don't see any risk in long term Bitcoin investment if there's any please i will love you to point it out for me so i will learn and become guided.
Holding for 5 years is not even long enough for me in terms of Bitcoin investment because there could be a higher probability that you may not see any good profit on your investment within five years because let's take for instance you are investing using $10 every week and if we calculate the total amount you will be investing every year is $480 and we multiply it by 5 years we should be getting $2,400 for the five years, so perhaps can see that there will not be any serious profit on your investment if you are selling on that short interval so instead of thinking about selling you should be more consistent on your investment till you arrived in a point were your portfolio is very big before you can think on that direction.
I was only giving an illustration for a proper understanding of my writing or what I'm saying, however 5 years is a good number of years to hold, it all depends on how much Bitcoin you have accumulated and your perspective of what you want,
If I'm investing $100 weekly in Bitcoin you don't expect me to stop accumulating same year someone investing $1k weekly will stop, me that is investing $100 may decide to extend my investment 10 to 20 years and he may decide to keep his 5 to 10 years.