Refinancing allows borrowers to combine there several loans into a single loan by taking out a new loan usually at a cheaper rate. The student loans you get while at school is based on the federal loan option, they not based on your credit profile. Once you start to work and build a good credit, you can significantly lower your rate and get out of debt sooner.
Moreover, interest rates have been falling for several years and so more and more borrowers have been able to save thousands of dollars by refinancing their loans or lower their monthly payments to a manageable level. There is also the added benefit of combining your several student loans in to a single loan and having a single bill. There is also a Federal loan consolidation option but it does not have the option of lowering your interest rate. Read More about benefits of refinancing.