There are four occasions that may warrant getting a disability attorney involved with your case: when you are applying for benefits, are receiving benefits, are in the appeals or litigation process.
It is not a good idea to apply for benefits on your own. Your application tells the story of your disability. If it is not done properly, you risk a bad outcome. Getting a lawyer involved will help you put your best foot forward and increases your chances of a successful application.
Even if you are on claim, you can be denied benefits if the insurance company decides you no longer meet the criteria. A lawyer can help you through the monthly review of your claim and deal with anyone who is hassling you or threatening to end your benefits.
You should also hire a lawyer if your claim has been denied, and you want to appeal. You only get one shot at getting this right. And if you must litigate, only an ERISA-trained lawyer has the experience and competence to present your case to the federal judge who will decide it.