Choose the right set
The best estimation sets are 3–6 reps at genuine effort — heavy enough that the fatigue model holds, light enough that form does not degrade into a different lift. Twelve-rep sets drift; singles test nothing. A hard 5 with two reps in reserve estimates within a few percent and costs nothing recovery-wise.
Calibrate with reps in reserve
The formulas assume maximum effort. If your set stopped with 2 reps in the tank, mentally add them (or use RPE-adjusted tables). Lifters who chronically under-load their estimation sets will under-estimate their max — which biases every percentage downward and turns the program into a gentler one than designed. Honesty in, honesty out.
The re-estimation rhythm
Re-estimate every 4–8 weeks from a fresh hard set — or immediately when the table stops feeling right. Between estimations, let the percentage-and-reps loop tell the story: loads rise when reps are earned. The 1RM is an operating parameter, not a trophy; treat it like oil level, checked on a schedule.