I replaced mine at 46,000 miles while doing the 40K service (a little late). The friction plates were still well within spec, but it appeared that the anti-judder ring had worn a groove into one of the plates. Given the time and effort to get to them I decided to go ahead and replace everything while in there. No more judder and definitely smoother shifting.
I did a
video on the 20/40K service (valve check, valve adjustment, timing adjustment, clutch change and bleed, fuel and air filter, and spark plug renewal ).
The clutch replacement is at 10:08......