Answer to vic86's question: Yes. Stay on a program for 6 to 8 weeks. The first couple of weeks are usually a breaking in period. Than, is the body adapting to the program, rather than should the body be adapting to the program, is the question. If after 6 weeks, nothing amazing is happening, than recheck the program and how you are doing it. Hopefully not adding your own tweaks to it.
If everything checks out OK in that regard, than might want to check out another type of program that can better the gains you want. 8 weeks if the program seems to be working for you. Longer, by a couple more weeks, it it fulfills all you wanted in a workout plan. 12 weeks may be the max you want to stay on any serious program. Always can go back to it after awhile. Good Luck.