For me it depends upon the situations. When I see the price of alts increasing then I must grab the opportunities.  I sell my alts rigth away so that I can gain  a big amount of profits. And when I see the price of btc still in a lowest price I will buy it because I  know that soon the price of btc will back to increased.  This is how I managed my investment in crypto currency's. We have to be smart and wise to gain a success.