All you hear about these Trading and Investing rules that " Dont put all your eggs in one basket " or " Diversify your portfolio "
(....)
There are also some people who are not believing here.
Their quote is "You don't need to diversify once you are in a good position and sized in", something like that.
Diversifying a portfolio is pretty good since this is applicable even you have a huge or small portfolio or capital.
But overall for me, the best is always "knowing or doing research first before putting your egg on a basket".