* You have perfectly mastered your form for a specific weight-lifting exercise. * Your workouts feel easy, like you aren’t working hard. * You aren’t seeing progress in muscle tone. * You don’t feel out of breath or like you need to take a break after your last set of reps on an exercise. * Your last few reps on an exercise are not slower than your first reps. * You can do an extra 2 reps (in addition to your standard number of reps) with the heavier weights. * Start with 3 sets of 15 reps for a particular exercise. If you can do that many easily with perfect form and without slowing down, you are probably ready to add some weight.