That depends on your total portfolio and the amount of risk you're willing to take @orlendgreat

This is what I did and will do: during the start of 2017 I had 20% of my total assets in cryptos, the top 5. I sold most of this during Q4 2017, and reduced my crypto exposure from 20% to currently 5% of assets. If I'm wrong, and Bitcoin does not drop below 10k, but instead goes up to new highs, then I still play along. Not for the amount that I could have been playing along, but I still make money.

If, on the other hand, my analysis does seem correct, then I have cash to buy back in during summer 2018.