On the other hand, I often find old thises and thats which are working fine with no visible deficiencies yet I still recommend replacing them. Modern things with newer technology 99.9% of the time are simply better and more efficient.
For example, recently I did an inspection out in the boondocks. The home had a 1938 oil-burning furnace in it. It was working fine with no visible deficiencies. I recommended replacing it, for a couple of reasons: First, it needed weekly maintenance 52 weeks a year because it gets cold at night in the mountains; Second, weekly maintenance is expensive, as is the oil relative to gas.
Electric panels to me are no different, especially these esoteric panels like Bulldog Pushmatics.