Weight Selection: How much weight to lift for a given exercise?

Progressive Overload is something you earn from a previous good training session.

When you train hard enough, your body will be forced to adapt and get stronger. 

As a consequence, you will be able to lift more weight or reps in the next session. 

All of the training programs in the Graduate Fitness Library have recommended reps and sets for each exercise.

In the above example you can see 8-10 reps is recommended. This means that you must do 8-10 reps of the Goblet Squat exercise with good technique. 

For each set to be effective, or “Hard enough”, you should be aiming to complete somewhere between 8 to 10 reps.
You should not be able to lift more than 12 reps. 

I am going to repeat that last part. 

You need to choose a weight that is light enough so you can just about do 8 to 10 reps with good form. Yet heavy enough that you can’t do 13, 14 or 15 reps.

For this recommended rep range it will mean that If you can do more than 12 reps with any particular weight then this weight is too light for you. 

Your body will not have any reason to get stronger by the next training session.