My Blue damsels are 6+ years in the tank.
Most of the others are over 3 years.
Starki are 2 years.
Surge was the last one added at the start of this year. Went in as a gorgeous damsel, and is now my ugliest looking fish. But the girlfriend loves he is more active than her Achilles Tang and won't let me try to catch him.
I should mention in addition to that list of damsels the tank has a total of about 120 fish. So it is a highly active reef community. I think with more fish there is a bit more chaos and a lot less aggression issues.
As for just the classic blue damsels, I have kept those in all my salt tanks for the past 25 years. I think they are still a spectacular fish, and they make sure any excess food is taken care of.
Dave B