Usually they recommend you to diversify your investment, so you avoid losses.
But as a real approach, having $1.5k, would you invest in how many cryptocurrencies ?
What if I invest little by little, only in Bitcoin, would that work as well ?
Its always advised that don't put all your eggs in the same basket.Its only related to altcoin investment which are highly volatile in nature.So by investing in two or more coins,even if one coin's price falls,another coin's price may increase which would reduce or just avoid the loss.But investing in bitcoin doesn't involve such problems as its price tends to increase gradually.