what exactly is mixing things up . adding more than two or more coins ? ah so its like diversify . this strat is the most recomended when it comes to investing and you cant build a strong portfolio if you only hold one coin .
Sometimes you buy and hold for the long term, other times, you take short time trades to get big profit.
short term trades is not the way you got big profit but its when you invest or hold for long time and you also dont need to confuse your self by doing both short and long term acts simultaneously because thats hard