Depends on several factors such price of the coins and the price charts for each coin. The frequent value that is often lessened from the value when the price drops or the frequent value that is added when the price increases. These are just several factors that would give you an idea of what coin to invest in, and what coin to buy the most.
In my opinion I prefer to have few altcoins as Long as it is still kicking and at the top of its existence among all altcoins. But then be always aware of the latest updates of altcoin or the coins you are holding so that you will not left behind.