"Never focus on the TOOL.
Focus on the PURPOSE."
- Bill Hinbern
Coach Bill is right. He said that focus on what you want to achieve and then look around for the available tool best suited for the task at hand.
Coach also mentioned that both barbell and dumbbell have their strong features, both have their weak points.
I am going to give TWO examples.
I'm going to prepare for my Olympiclifting competition. I would like to spend more time with the barbell to perform Snatch and Clean & Jerk, and spend more time to do Front Squat and Back Squat with the barbell to improve my strength.
At the beginning of each training, strength training is my first priority, then I will do additional hypertrophy training to support my muscles.
When I'm preparing for my Bodybuilding competition. I would like to use more variations to train different muscle groups. I may not start from Barbell Bench Press, I may start from Cable Flye to activate my pecs muscle, then Inclined DB Press to Flat DB Press,
Flat Bench Press can be the last exercise of my program.
Similar to the Leg Day, I may do Back Squat 5 sets x 12 reps after all leg exercises. Depends.
The important thing is to get out there and DO IT!