Ask if there is any part of the case that you can handle on your own which might save on legal fees. If you want the particular lawyer you interviewed, make that clear and change the retainer agreement. On the other hand, having a junior attorney do some of the work on your case will save you money because the firm should bill them out at a lower hourly rate - ask. A retainer is a lump sum of money paid at the start of your case against which the attorney will bill at the hourly rate. You and the attorney will sign a retainer agreement which outlines your rights and responsibilities to each other.
Attorneys sue clients for non-payment of fees.
Make sure you have a payment plan that you can handle. Ask your attorney if there is any philosophical difference between your views and those of the attorney. If the attorney disagrees with your value system and tries to talk you out of something you believe in, run out the door. You will be in conflict with this lawyer sooner or later - get out now. This is an extremely important question.