I don't even look at the price anymore. Just looked today after a few days... Eth is now being negotiated at 480. LOL
Nobody knows how much my portfolio is worth. I will hold for a few years. I am not going to sell now, even if it were 10x more than it is now, so why would I care for the price now?
I really believe in the technology, I really like it, I am even studying it. I am not worried.
Yes, that is a good principle for people who play longterm. It is highly recommended but you should get additional work if your capital is fully in Ethereum coin.
Ethereum is not just an altcoin, its technology is needed by ico developers and is currently very successful.