Alternators,,, are they worth saving?

These days it is hard to get alternators in stock amperage that matches the rest of stock wiring system. After looking for months, I went to a rebuilding service that turned out my old unit, completely rewound in the original amp rating at a great price. I even tried to take a new 100 amp unit in and get it toned down, but evidently that's really expensive to do... go figure.