depends, I also often sell all altcoin I have, but I sell them at high prices. just like playing trading, I sold it for bitcoin, and buy altcoin when the price is low back, as it continually until I produced a lot of bitcoin 
You are absolutely a good trader. Must have earned good already I guess. We have the same strategy in trading, the golden rule always applied in this gamble. Buy low then sell high.
That the basic in trading so that you can profit no matter what its just that sometimes its hard to see which alt coin to investment and which is not because of the hype of some altcoin users/investors.