I live in a condo (40ish yo) and recently a neighbor in an adjacent building had a leak and the board suggested that everyone have a plumber come inspect their units. I just inspected and found various levels of corrosion at most joints with the included photo the worst looking of the bunch.
How concerning does this appear?
Thanks for the input. I will look at getting a professional in the near future. The city's water is pretty good, so I wouldn't expect it to be the issue, though no guarantees. I'd suspect bad solder first or the number of joints based on your response. Over 3/4+ of the joints look similar including color, though not as bad as the one in the photo.