I follow quite a few hair blogs and because of that I come across girls lamenting that their hair is not progressing as quickly as they wish it would. I was also one of those girls. My hair was stuck at APL for months and would not get longer. I figured it was due to slow growth, to dusting my hair too often and at one point, I even thought I had reached my terminal length. In the end I realised my problem was slow but steady breakage of my ends. In my case it was due to heavy product build up. At first I was unable to identify the problem because my hair felt as if it was in protein overload. I therefore stopped using protein and tried to increase moisture in my hair but continued using the products which were causing the problem in the 1st place. In the end I lost a lot of hair.
I would caution anyone, if your hair is still stuck at a certain length after 6 months and is not due to any major setback, then it is time to reassess your regimen. It is time to do a 6 month comparison length check, placing your photos side by side to figure out what is going on. You might be surprised that you are not retaining your length.
My hair in October 2009: The successful days of my journey. Went from NL/SL in January 2009 to past APL in October