A Dying Concept Trimming and Adding May Not be Necessary

Where’s the Value at?

We buy based on a multi-year horizon, but have found that it typically takes about 12 to 18 months – if we’re right – for the market to recognize the value. If something you considered truly cheap hasn’t shown any signs of working after 18 months, it’s generally a good idea to make sure you have a new reason to keep it, because there’s a good chance your original thesis was wrong.
Source: http://www.valueinvestorinsight.com/