I'm booking 10% profit from each coin bought for long term. I'll again buy them at new year start

Very good practice, all the coins be it alt or big cap coins will see a downfall, that will be the one last time people will get discount on them.

Not to forget there is a probable dump before the bitcoin halving as well so that can also result into the final resort for the crashed discounted price but after that no one will see that happening.