First off, you are still a beginner because you can't spell it haha, just kidding man.
For your first question you don't necessarily have to change up a whole routine based on some set number of weeks. Keep doing what is working, if some exercise or technique isn't then change that, but you don't need to throw the baby out with the bath water. Advanced techniques are just that, advanced, so you likely won't need or really benefit to much over regular straight sets at this point. You can have different variations of exercises, but they aren't required really.
I don't think starting over a routine from scratch is beneficial. If you are doing a program that requires 10 rep squats and you start at say 135x10 and over months and months build up to 295x10 it would be silly to start again down much below 250ish at the lowest. Progress on weights in basic exercises in whatever fashion you deem best for you at this point and be consistent, that's all that really matters.