This question is highly subjective first off. Second, whether or not you decide to keep your beard, you should always present yourself as a professional during an interview. We believe that this means that you should be well kept meaning that you should form your beard and trim it where necessary in addition to shaving where necessary. As a general rule, if the job requires you to not have a beard, you should evaluate whether or not it is appropriate for yourself. Generally speaking if you work in the public eye, are in sales, are required to wear a respirator, or are going for a leadership position, you are generally expected to be clean shaven. Where the wrench comes in, the times are changing and beards are more acceptable in a variety of working environments than they were 10 years ago.