Currently I own a lot of altcoin, I bought them at ico. My account is being downgraded several times. There are many people who say bitcoin will continue to decrease, so altcoin prices also decreased compared to USDT. So now, should I sell them and wait for the price to buy back? Give me advice 
hold or sell? it is easy in my opinion , im selling most of my altcoins after they went to main net, but if i really believe in project im keeping some amount of them