Some people make the mistake of selling all there Bitcoin just because they want to start a new business or investment with the money and after selling it and the start there new business or investment some time later it crashes and they lose it and also lose their bitcoin investment so keep your Bitcoin investment going while trying out other business or investment.
Selling our holdings at once is never a good practice, I'm sure that Majority of this people that like selling all there bitcoin are those Investors that have not accumulate enough stash of bitcoin in thier portfolio they feel that after selling it that it won't take long to accumulate it back. While those Investors that have been struggling to reach the status of overaccumulation can only sell 5 to 10% of thier holdings whenever it double and after that will have to allow it to compound upon itself before attempting to sell again, because they know how Long it takes before they were able to reach the status of overaccumulation so they wouldn't want a situation where they will start the accumulation process all over again.
I think someone who would sell all his bitcoin assets is really not an investor, but someone who is only interested in quick profit, even if you have gotten to your goals of buying and accumulating bitcoin it’s more important that we should take our profits that is only maybe if I have gotten to my years of over accumulation, that is quite understandable, but taking all my profit and selling all my bitcoins, hell no I can’t even think of doing that after all my years of working and buying and stacking bitcoin, it might be very hard to start all over again considering how much time and money that have been invested, that would be a financial disaster selling all my Bitcoin assets.
So what's your purpose on investing if you don't have plan to sell? taking profit is actually not bad if you are in over accumulation stage or already in 5 - 10 years of investing on Bitcoin. But you should not sell everything since somehow there still more great things will happen on Bitcoin.
But if your plan is for retirement then there's nothing wrong with that, as long as you know the future consequences of the decision you have done and make sure you have back up funds so that if something bad happen on Bitcoin you will not became an old broke and doesn't have anything left to sustain your daily living.