I have a Linn Karma, sounds very good, bought new.
Not easily bettered at any price!
I liked my Karma on LP12/ Ittok in 1983 for 5/6 years, but it can certainly be bettered; the Troika was generally thought to be an advance but with the same sonic signature.
As I've had a number of higher end cart's since on different decks/arms, comparisons are odious, as they say, but each has been an improvement on the last. I think, in that presentation ball-park, there are offers from Lyra, the late Transfiguration and, I'm sure, many others, which would put the Karma in the shade. It was very good for its time and usage; that's as far as it goes, i.m.o.
I have a 14/15 year old Urushi in my drawer which I hope to re-mount or replace at some juncture. I'd be gutted to think that the suspension, and indeed the stylus, would be significantly worn, having been mounted top arms (incl. 2 x 12")
I guess that set-up is of prime importance to stylus life, but, apart from large temperature variations as Dimitry, above, says, I haven't a clue about the longevity of upmarket suspensions. Possibly this is as variable as the quality of manufacture.