This from @bretcontreras who is recently a guest on the Huberman lab podcast discussing resistance training. With proper intensity, 6-7 (work) sets per muscle group per week appears optimal. This squares with my experience. Even fewer sets (3-4) if you go to failure.
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Obviously, these are guidelines. It’s impossible to gauge effort for everybody. Some people really know how to push to failure others don’t. Most important is good form. And progressive overload by adding weight or repetitions or both on a regular basis.