You must break down muscle tissue when you train in order to build muscle.
If you do this with high loads(force on muscle tissues) it will be effective.
The Scott Alexander training system is the answer to these questions.
personally i beleive that consistency is most important as in EVERYDAY TRAINING with ZERO days off
ive been painting and working on houses and construction jobs for YEARS and NEVER stopped working out
i never worried too much about lifting heavier just DOING it every day and not givin a damn about people telling me im overtraining
the human body can be an immortal workhorse slave machine, that was our design
but through the years of misinformation the human kind has lost its confidence and knowledge
one must make up a reality as if they were the only human for survival and only could rely on themselves (meaning NO days off! because you have no one to rely on but yourself)