Training equipment choices include free weights (such as barbells and dumbbells), selectorized weight machines, plate-loaded weight machines, cable machines, and equipment for body-weight exercises such as bars for chin-ups and dips. The selection of equipment depends on the desired outcome. In general, for strength training, free weights should be used predominantly, with some machine, cable, and body-weight work. In general, for muscular hypertrophy, relatively equal amounts of free-weight, machine, cable, and body-weight exercises should be used because machines are able to isolate specific muscles more effectively than some compound free-weight exercises.
Volumes of literature could be written on the ongoing argument between the use of exercise machines or free weights, but here we shall conclude that both are important and complement each other in muscle training. The most effective way to make progress is to use machines whenever they are more appropriate than free weights, and free weights whenever they are more appropriate than machines.
Because all forms of strength training equipment offer different advantages and are limited by different disadvantages, it is best to use a variety of training equipment in your strength training program. There are many areas you will never be able to train efficiently using dumbbells and barbells. Also, there are many exercises for which dumbbells and barbells are the worst possible choice.