Turntable set up- How easy is it

I was brought up on the conventional wisdom too - 100 hours or so, but I never did understand the mechanism. It sounded a lot like a practice from WW2 where riflemen from US and UK would exchange a single round (.30-06 and .303), fire it, and find that their rifles shot better.

Then I heard the word from a manufacturer. Who would know more about cartridges breaking in than a manufacturer? Only a rebuilder. And Soundsmith is both. So I accept their considered opinion until I have very good reason to change.

Fiddly, yes, but worth it in longevity, I think.

I don't have enough experience to insist on anything. However, he is one man, and there are other cartridge manufacturers. For example, Nagaoka states 30 hours, and they don't say it will be fully burnt-in after that.
Anyway, if it doesn't or almost doesn't need it, that's perfectly fine. I just never encountered a high-end device like that. It varies wildly, true.
Who would know more? Well, people don't always say everything they think. I believe, Vladimir of Lamm said that his amps would work well with any good quality power cord. And that's true. What he didn't say was that they would work even better with great quality matched cord. Lamm/Purist Audio/Kharma set-up was consistenly considered one of the best by many. Another example. My tuned Nakamichi deck exceeds factory specs and with Purist Maximus cable and Maxell Vertex tape sounds far better than guaranteed by Nakamichi in 1981. They might've tested it with the same quality cable but I doubt that they insisted on using it. So, I don't think that Peter tells the whole story.
In any case, if I hear the difference, I do hear it. It can be subtle and it can be not.

All stylii have a suspension and the suspension will compress a little during its life time. Which is why user adjustable VTA is a good thing.

Its not that hard, but it is exacting. Be prepared to spend days before it's done.....actually it would be beneficial to tweak it from time to time thereafter. You should have the proper tools...good light, a quiet safe desk to work on, including all the usual things.

Setting up a TT is not too difficult. But it takes trial and error to get it done to a satisfying setting. And you have to be very careful on how you handle the cartridge. I was setting up a McIntosh MT 10 for a friend and my finger pass the stylus and it fell off in my hand. I had to send it to Sound-smith to get it repaired. Good thing I had a backup cartridge. I have a VPI Classic IIl which I set up myself. You did not say what TT you have.