We need to recognize the difference between a useful advice and something that can ruin you if applied incorrectly, holding for the long term is widely recognized as one of the safest and best ways to invest and make profits, however this is only true if the projects in which you are investing have very strong fundamentals and in this market the number of projects like that are incredibly limited and as such you must be very careful with the kind of coins you decide to hold for the long term.
Splitting good projects from shit assets, you need to dedicate your time in sorting every projects and see if that's qualified to how you project the coins potentials, advice and opinions are also usable if you know how to pick the right one from those who are just hyping what they've already holding.
This market has a high volatile nature. If you don't do your homework, it's easy for you to lose your money.
There's no need to hold altcoins in the long time I think that's right for me. I'll hold them in the short term. When they pump then I'll take profit. They will usually return to the cheap price when bitcoin's bearish trend. So I'm going to sell when it's a bullish trend, so I don't hold it for a long time.
If you find this strategy very effective in your investment, why not right? Buy when the hypes still fresh.
Sell it up as quicker as you can, to make sure that you benefited from this investment, rinse up and keep repeating for more possible profits.