Probably not to different from refactoring the same CRUD applications over and over to keep up with with the other poor bastards who had to do it first.
That’s a pretty bad analogy because you don’t refactor for maintenance. A better equivalent would be swapping out hard drives in a major storage system or servers in a data center on the scale of Google. It’s mind numbing work but it’s better than many other “pick and place” style manual labor. At least with painting a bridge the scenery is better although the temperature is more harsh.
Except you get exercise and fresh air.