What is your target on Bitcoin when the price rise to $20000?
I will withdraw some(50%) of it and leave the remaining(50%), by investing into more altcoins(with 10%) holding the rest in bitcoin. Cause taking all is not the best and there is a strong possibility that the price will continue to rise.
I have exactly the same idea that when it reaches $20000 i might withdraw the 50% and leave the other half, and it is good to spread the investment like putting to some altcoins that has a potential of rising up too, but of course majority believes more on bitcoin that it has the capacity of climbing up to the moon and thats what everyone is waiting for...
If you cash out half your bitcoin holdings, it might be better to cash out in fiat rather than convert it into altcoins. Crypto has had a great rally in 2017 and you might want to enjoy the results. No point in going into an investment which is of higher risk (altcoins). If you want to gamble and are in cryptos for the thrill, then there is no harm in alt-trading.