Just like stock, you can invest all your money for a coin code if you really trust. But that would be very dangerous. One can make sure that the coin will not fall down to 0 a day.
The advice is to diversify your portfolio. That will help reduce the risk. You do not earn much but if not lost also much.
All we do is depend our decision.
I prefer to split my money into some different project to prevent high loss. Of course the profit that we get also smaller. But sometime the altcoin can hype till 100x and its big enough. Put all egg in one basket is very dangerous.