Some lawyers would take any case that comes their way. They wouldn't carefully select the cases they can handle with their knowledge. They just want to get as much work as possible, not caring if their legal knowledge would serve the client needs or not. Don't use factotum lawyers like these. Lawyers who care about solving their clients' legal needs are always specialized.
When you are facing a legal issue, a part of your life is at stake. The solution to that problem will probably decide the direction of your life for the time to come. In a situation like that, you want legal advice from someone who knows every law, every bylaw, and the whole case law related to your specific case. You need someone who is specialized in the right practice area and can guide you through the process with his or her vast experience.
That is why you shouldn't use a lawyer who is Jack of All Trades. General practitioners know a little bit of everything, but they are not really good at anything. Choosing one of them to be your lawyer might be an opportunity for him or her to learn the tricks of the trade. But you can't afford to let someone use your legal issues to learn the ins and outs of the specific practice area. Hard times call for a specialized lawyer who knows his or her job.