I am the guy who holds in long term. So for me, bitcoin and ethereum prices are fine to buy now. So i can say that its time to buy it.
I also believe that now is the time to buy BTC ,but how much of it will have to keep in your wallet so the price has increased I don't know. In my opinion this winter it will be possible to sell at least one and a half times more expensive than it costs now.
I think so too, but I think that the main growth of all cryptocurrencies, including ETH will be only in 2019. For growth in 2018 do not see any prerequisites. Perhaps we did not see a price of $ 50,000 , as many analysts say.