when is the right time to sell your mutual funds?

dear friends,

                 i came across this article on a famous website.

http://www.moneycontrol.com/news/mf-experts/when-is-itright-time-to-say-goodbye-to-your-fund_912101.html?utm_source=MC_Mail_Mkt_Alert

Would like to hear your comments as after reading it i am confused .