Kevin M. said:

........My thoughts are that you learn it well enough to play but not master because months later you can come back and find that same lesson extremly easy.  Am I wrong. Your thoughts on this will help.

Kevin, the thing is that when you have worked long enough on an exercise you can get tired of it and not work well at all. All exercises help in one way or another so that you don't really need to stick to one till it is perfect. Do the best you can till it satisfy's you then go to something else and as you said you can come back to it later when your technique has improved. Do everything diligently. Enjoy and make the best out of it.