After You Complete a Bachelor's Degree

Curious6

I have a question regarding what to do after you complete your undergraduate study period of 3 or 4 years. Once you graduate, what is best for students interested in economics or management degrees? Is it best to work for a few years and then apply for a Master's degree, or go on directly to graduate studies? What is usually the average age for a person to start graduate studies?

Furthemore, I am quite confused about what graduate studies really are and how employers value them. Are they primarily research-based, or more case-based such as the different MBA programs? If somebody could please clarify this it would be really helpful! Thanks in advance. :)