I will hold VHL for long term since I see the potential here....

I will hold VHL for long term since I see the potential here. Just not quite sure should I keep investing into VHL or should I invest into other dividend stocks to diversify? I only have 3 stocks in my portfolio at this time, and I read a book which suggests 10-30 stocks for a diversified portfolio.

Thank you for your reply, I will keeping learning and researching, and I really like HC and this forum has taught me a lot!