Altcoins are really scary, if you can do some research you will see many good altcoins that had very good start and value in 2018 and are still alive today but we never heard anything good from them anymore for some reasons, they are now like ghosts, honestly altcoin investment is more scary, this is why its better to always take profit, most especially from new altcoins, Profit is Profit, either big or small.
I have followed this strategy myself but believe me for forex or commodity market it can work but in crypto market this strategy will give you more stress and confusion because everytime you take profit you will regret that your profit could have been bigger if you have waited more.
It all depends on how the price of the coin you sold further behaves. Of course, you always want to make the most of your profit. However, it is worth understanding for yourself that it is much better to get at least some profit than losses.