And what do you when it does not retrace and runs up to 11k, 12k. Do you fomo in then?
I'm pretty sure you would.
And then we retrace to 8k and you may think:" God I'm so dumb." 
There were guys like you last year around the $3k price. They sold and thought they will buy back in at 1500. But the price moved to 5k, 7k and they all fomoed in again.
What I want to say is, you don't know what's going to happen in terms of price, therefore this strategy of selling all and hoping for a crash to buy back in again can by very pricy. Don't be that fool. Sell a bit, but not all!