Apart from some light auxiliary RTC work, my workouts consist of bodyweight squats, inverted rows and push ups, the two latter in the form of lighter versions on the bar of a Smith machine.
I have been steadily making progress by increasing reps from 3x3 to 3x15, then lowering the Smith bar and starting again with 3x3... But I started today a new inverted row cycle by lowering one step the bar and trying 3x3 and failed. It is simply too hard. Going back by raising the bar a step and 3x15 makes not much sense, I think, since I am already able to do that (In fact that is what I did after seeing that the new level was impossible).
Should I add one auxiliary exercise? (Dumbbell bentover row / Barbell row / Cable seated row are some options I am thinking of, as well as something more vertical like the lat pulldown machine). Or should I simply insist and keep on trying until achieving 3x3 perfect-form, slow repetitions? - I would like to maintain the workout length to a minimum in order to stay away from overtraining and to focus my body resources on making progress in a few basic exercises.