Using the same weights or machines can become monotonous and boring and nothing kills an exercise regime like monotony. That is why it is beneficial to switch it up and incorporate some bodyweight exercises.
What are bodyweight exercises? The exercises everyone did before there were gyms. The exercises in which you use the weight of your body to provide the resistance. Push-ups, pull-ups, sit-ups, lunges, squats and wall-sits are some of the best known examples of bodyweight exercises.