It’s interesting to compare these long lived airframes with older designs. The Puma is now the Mk2 version, after 50 years. The Spitfire was only in RAF service for some 17 years and yet the final version was the Mk24!
Although the Puma had some rather awkward limitations and nasty vices, Aerospatiale did alright with it, by my reckoning after over 2500 hours on them.