There are a number of reasons that someone may need the help of a criminal defense lawyer. Top Ten Criminal Defense Attorneys, but a conviction on your record can cost you over and over for the rest of your life. First of all are the very real possibilities of large fines and time behind bars. However, even misdemeanor convictions can keep you from getting a good job. Although many potential employers will tell you that they will only check back through 7 years of your criminal history, that is largely a myth.