When I come across an old, beat up looking Federal Pacific panel, I will insist that it be replaced. Usually they are the old, 8 ckt, main lug type and the breakers feel sloppy when operated manually. Sometimes however, I see one that looks and feels pretty good. The breakers all click nicely and they usually have a 100-amp main. I know this doesn't reflect reliable performance, and I would prefer not to connect to it, but it is harder to convince someone to change something that looks good.