Holding more altcoins is recommended because we cant predict which one altcoin rise in the future and which one dies. So by doing this you could reduce the risk.
We all know going all in on one coin is bad. But still there are people who do it or have two coins. I'm not saying more is better but it won't hurt to havo couple of coins. DYOR and invest in more coins.
A new coin I invested in is TIX if someone wants to check it out, they have new website and new ambassadors, Randy Jackson and Kenny G.
Be smart and invest in more alts.