Whether you're new to lifting weights or have been doing it for years, you're just as good at guessing how many more reps you can do before your muscles give out.

When people lift weights until they're almost too tired to continue, especially with arm exercises, they get better at guessing how many more reps they could do. It's like training your body to feel its limits more accurately.

When people do more reps in a row during weight training, they become worse at guessing how many more reps they could do. This means longer sets make it harder to judge your own effort accurately.

Lifting weights until you can't do any more reps doesn't make you stronger than stopping a few reps short, according to a big review of studies.

Lifting weights until you can't do any more reps makes your muscles grow bigger than lifting weights without pushing to your limit, based on a big review of studies.

Lifting heavy weights at least twice a week, doing full movements for a few sets each time, and doing it early in your workout can help healthy adults get stronger compared to not exercising or doing other types of training.