its still depends the coin and where,
if you buying unlisted coin, or it still traded on not official exchange then you can hold for mid or long
but if the coin already popular and added anywhere you might just catch dip and sell for 10% or 25% profit
Great this is the way I usually use. I bought the altcoin in the top 100 and kept them and sold when I gained 10-15% profit. And I bought some tokens after the ICO ended and waited for them to be listed at the exchange. But this is quite risky because the tokens may fall after being listed and in 2018 most of the tokens I purchase fall 2-5 times after listing at the exchange.