Not an american thing, but rather old-fashioned. A long time ago, well-to-do Britons had a "family lawyer". Not on retainer; but he knew the family business (so didn't need briefing), and he dealt with wills, property, that kind of thing. Like a family doctor, rather than a specialist consultant.

Nowadays only the very rich can claim to have a "family lawyer".

Some people do but usually the "have your lawyer" phrase means "find a lawyer who specializes in this area and contact them". Still, the point still stands, it's expensive and time consuming to even begin the process of engaging an attorney if you haven't done so before.