Not that I don't know the difference between what they are and various exercises one can perform with each, but what would you say the respective advantages and disadvantages of each are? Currently, I just have dumbbells and wonder if there are some things I will need a barbell for. I realize that dumbbells are going to force each arm to act alone whereas a barbell will require the arms to work together, but how will the difference affect my muscle development? Also, regardless of what I'm suing, how can I decide what I can safely do withou a spotter and what requires one? Thanks.