To whom it may concern:
I highly recommend that a letter of reference can help you land that next job.
When a recruiter or employer has several candidates to choose from with similar credentials and experience, having a letter of recommendation can be the icing on the cake. If someone has the confidence to include a reference letter from a previous employer with their resume, that is generally a good sign that they have the matching skills.
For a letter of recommendation to actually have some influence however, it must carry some weight. Letters from professors, directors and other people of prominence are always great, while letters from former managers or co-workers although important may carry less overall weight. Still it is very important that any letters of reference are a representation of a persons real talent and work productivity. This is why having references from people familiar with your direct work is very important.
In closing, I would highly recommend having a letter of reference from an influential person in your life to secure your next job.