Workouts without tracking become repetitive guesswork. A simple log (weight x reps for each exercise) reveals whether you're actually progressing and surfaces plateaus before they cement.
The minimum useful tracking
Weight x reps for each exercise. Date. Brief subjective notes (energy, sleep, mood). 30 seconds per exercise. Apps (Strong, Hevy, FitNotes) make it frictionless; paper notebook works fine too.
What the data reveals
Progressive overload happening or not. Specific exercises stalling (programming or form issue). Weeks of underperformance pointing to under-recovery, poor nutrition, or sleep problems. Long-term trajectory (most users dramatically underestimate progress without data).
Tracking takes 30 seconds per workout and changes how you train. Most plateaus disappear once the data makes progression deliberate rather than vague.