If there is some kind of buildup on the hair will you have to use stronger shampoo to remove it.

Mild, sulfate free shampoos are great for weekly maintenance cleaning but they are formulated specifically so they won't strip the hair of oils so they won't remove a lot of build up. If you use styling products it is likely inevitable that you will have to break out a stronger cleanser from time to time. The important thing is to use something that is very gentle for your normal maintenance routine.