1) 850-1000 out of a high quality nude conical.
2) 2,000-2,500 hours out of a high quality line contact or microridge.
This is overestimated so much in my opinion, especially for nude high quality conical.
in my vision it is more or less like that:
300 conical
400-500 elliptical
600-800 shibata and line contact
1500-2000 for some micro ridge and microline
up to 2500 only for some exotic profiles like Replicant-100 or Gyger, VdH